Plugin Name

zLinks is a service expressed on a user's client that enables all links from within a blog post and its comments (or from a CMS -- content management system) to be displayed with additional and related data and information. zLinks thus becomes a nexus -- or jumping off point -- for additional exploration and learning. In this specific instance, zLinks resides as a plug-in to WordPress; other instances may also occur as plug-ins to existing client-side software. The interlinkable linked data phenomenon underlying zLinks is a key underpinning of the semantic Web, and an expression of the unique technologies and data mastery provided by zLinks' parent company, Zitgist.

The Internet and the Web first showed the power of linked and networked documents. The interlinked links provided by zLinks takes this understanding to a new level: the freeing and linking of all data objects and concepts with related information. We have seen a bit of this trend in the past few years with "mashups" that are able to, for example, plot geographic information from one source onto a different map source, or time-related information on calendars or timelines. But these first baby steps required specific coding to make data from two different sources relate. zLinks now offers a single facility for exposing data linkages everywhere and in any form. These linkages are a floodgate about ready to open. The value is that related data will find itself and find its relationships by virtue of its linked character and quality. The added value to standard Web users is limitless.

No, there is nothing you need to do in advance. It is useful to already have a personal URI, FOAF file or OpenID, but those can also be obtained after initial installation; see this other link.

The current zLinks download is always available directly from the WordPress download site at: http://wordpress.org/extend/plugins/zlinks/.

The most recent version and upgrade instructions may also be found from the same WordPress distribution site.

1. Upload the folderzitgist_browser_linker to the /wp-content/plugins/ directory
2. Activate the plugin through the 'Plugins' menu in WordPress

Yes, zLinks requires the cURL utility (see http://en.wikipedia.org/wiki/CURL). Fortunately, this utility is a standard inclusion with PHP and virtually all users should experience no issues. If it does pose a problem, the link above will lead to further information to fix the problem.

You must initially set up zLinks before you can begin entering annotations. Like other zLinks configurations, you make these changes within the Options ? zLinks menu links within your WordPress Administration panel (see http://codex.wordpress.org/Administration_Panels). All configuration options are set via radio buttons and simple fill-in text boxes.

You must set your author identity prior to being able to share your annotations publicly on the Semantic Web. This identifier is used to link the annotations you wrote with the URL you annotated. You may select from three options to set your identity:

1. ( ) Use the generic WordPress ID number: http://blogname.com/wp-content/plugins/zlinks/user/$userid
2. (x) Reuse an existing identifier (the URI describing you): [enter URI]
3. ( ) Use a new identifier at a later time: http://blogname.com/wp-content/plugins/zlinks/user/$userid; link it to this new identifier once obtained: [enter URI]

You may keep your annotations private or share them publicly with others on the Semantic Web. When public, whenever another person links to the same URL you have annotated (say, the URL http://example.com) and also has the zLinks plug-in installed, then readers of that reference blog will also now see the annotations you wrote for that URL. By disabling this option in the configuration dialog under Options in your WordPress Admininstrative panel, your annotations will only be visible from your blog and will remain private internally to the blog and its authors.

When you mouse over the small icon at the right of a link, zLinks launches its data link analysis. You will first get an alert that the system is working, retrieving all of the necessary background link information. You will then get a popup showing the results. The popup results are presented in up to four sections. The top section contains some general zLinks links (to this FAQ, for example!). The second section presents links to either the standard Web page or the semantic Web page (resolved) for the initiating link. The choice of this link depends on the content negotiation dictated by the starting URI in the embedded blog link. Additionally, there may also be some actions in this section related to certain types of URis (such as those with a book or product reference on Amazon, for example). Often, these additional actions and links are coded by a unique site icon. The third section presents any annotations, if present. The last and bottom section presents a more disaggregate view of related resources (data objects) with each link representing a unique "triple" drawn from the contributing information resources enriching the link. This listing can get quite long, and is therefore also keyed by icon to indicate the particular kind of resource that each triple link represents (person, document, subject, music, etc; see further below). Clicking on one of these links takes you to a Zitgist Linked Data Server (ZLDS) with its results presented through the Zitgist Browser, where various views and data formats are displayed (again, based on data type), with still further links for additional discovery. These Zitgist views can themselves be quite rich with maps, timelines, photos, structured data, etc. Here is where the data discovery part is really fun!

An incoming reference (or "backlink") is a external link pointing to your content. A 'backlink' is akin to being the object in a subject - predicate - object triple. All incoming references or backlinks are shown in the first column of the zLinks popup as a twisted arrow icon, or little back arrow.

When you mouseover an incoming reference ("backlink") icon, the tooltip shows a message similar to: Incoming reference has predicate: link_to Remember, an incoming reference is based on an external object referencing your current entry with a form similar to something like: <?p> Where the form corresponds to the standard triple of . (The predicate is called a property in RDF, but it is the same thing.) Depending on the backlink (that is, the incoming reference) the predicate may be any of the relationships from a source. Common ones are linked_to, homepage, see_also, sameAs, and so forth. These variations can not be enumerated in advance because the actual predicate relationship name in zLinks is based on the nature of the source triple. As you become familiar with the nature of these data relationships, inspection of these 'backlinked' tooltips becomes even more valuable.

There are a few common application icons you will see in zLinks (these are separate from the resource type icons; see below). Here are these icons and their explanations: Standard zLinks link icon standard zLinks icon that calls up the links popup zLinks link with annotation a zLinks link that includes annotation(s) working icon icon indicating zLinks is currently working . . . . Annotation popup icon Annotation popup icon (authors only; click to invoke) annotation indicator icon icon indicator for annotation edit icon edit an existing annotation (authors only; click to invoke) delete icon delete an existing annotation (authors only; click to invoke) backlink icon icon indicating an incoming URI reference ("backlink") Web page icon icon for a standard Web page link close icon Close dialog icon

To make a link annotation, you first must be logged in as an author of the blog (via having accessed the Administration panel). As a logged in author, you can then single-click on the zLinks icon, which will then bring up the separate Annotation popup. You simply need to add information in the text box to create your specific annotation. Note you can do this multiple times with multiple, separate annotations, or edit or modify existing ones. When you are completed with your entry, click the Save button to save your entry to the database. If you click off of the Annotation popup without first saving with the Save button, the dialog will close and nothing will be changed. However, if you return to this dialog in while the session remains active, you will see your previous unsaved changes. Note each time you create or delete a new annotation, zLinks pings PTSW (http://pingthesemanticweb.com) to update your listing if you have made it public (see above).

You may provide an overall annotation relating to a specific blog post in its entirety (including, as examples, categories or tags) by annotating the link associated with the post title.

Simply bring up the Annotator for that link and click on the edit icon for the specific annotation you wish to change. You will then get the text box to edit your entry. When you are done, click the Save button to update the entry and save it to the database. To close the dialog, click outside of the popup.

Simply bring up the annotator for that link and click on the delete icon for the specific annotation you wish to delete. The entry will be removed from the database.

Yes, you may provide as many annotation items per link as you wish.

Annotations are also separately available as resources at this location: http://blogname.com/wp-content/plugins/zlinks/annotations. Annotations can be referenced as rdf+xml, turtle, or rdf+n3 (application or text). In addition, the annotations can be obtained in their entirety or by individual post. The URIs are properly handled so that the information is available to both browsers and as RDF.

Yes.

At present, there is no limit. Also you can add multiple annotations per link as separate entries.

The zLinks interlinked data is not kept permanently on the Zitgist servers. Each time you access a new zLink, the references are retrieved anew. This is most often not a problem, but can be on occasion if either: 1) the sources of the interlinks are slow; or 2) there are many, many interlinks. The latter is not yet that common, because linked data is still rather young. But it will grow to be a consideration and can crop up now when some of your sources are really "semwebby." We will likely need to change this behavior in the near future, but, for now, you may encounter a linked site that does an awful lot of "thinking" before your get your full results. By the way, if it ever is a problem and you can't wait, simply move on. Just move your mouse! No harm will happen.

These are the standard icons provided with zLinks and the name of the rdf:type to which they match: amazon icon amazon annotation icon annotation article icon article channel icon channel comment icon comment document icon document entry icon entry feed icon feed group icon group info icon info musicartist icon musicartist musicgroup icon musicgroup note icon note onlineaccount icon onlineaccount organization icon organization person icon person personalprofiledocument icon personalprofiledocument point icon point post icon post project icon project record icon record semanticpage icon semanticpage solomusicartist icon solomusicartist

Any data resource link that appears in the lower portion of the popup may have its own associated icon. To do so, create an icon for the type you desire (advised to keep to 16 x 16 maximum), and give it a name with the GIF extension exactly the same as the rdf:type name used to refer to it. Then, place the same-named item.gif in the /imgs/ directory of your zLinks plug-in. You may add as many icons directly related to specific class names as you wish. Examples of the existing icons pre-loaded with zLinks are provided above.

Submit any support requests that are not obvious on the Web site to zlinks-support@zitgist.com.

The semantic Web is an evolving extension of the World Wide Web in which web content can be expressed not only in natural language, but also in a format that can be read and used by software agents, thus permitting them to find, share and integrate information more easily. It derives from W3C director Sir Tim Berners-Lee's vision of the Web as a universal medium for data, information, and knowledge exchange. At its core, the semantic web comprises a philosophy, a set of design principles, collaborative working groups, and a variety of enabling technologies. The most compliant versions of this definition are generally referred to in all caps as the Semantic Web, while lower case usage represents a more relaxed version with non-RDF data.

Resource Description Framework (RDF) is a family of World Wide Web Consortium (W3C) specifications originally designed as a metadata model. The RDF model is based upon the idea of making statements about resources in the form of subject - predicate - object expressions, called triples in RDF terminology. The subject denotes the resource, and the predicate denotes traits or aspects of the resource and expresses a relationship between the subject and the object. This mechanism for describing resources is a major component in what is proposed by the W3C's Semantic Web vision in which automated software can store, exchange, and use machine-readable information distributed throughout the web, in turn enabling users to deal with the information with greater efficiency and certainty. With respect to the semantic Web, RDF is also used by a number of reference vocabularies called RDF schema that provide common concepts for relating resources to one another. It is this commonality of reference that enables data to be linked. RDF's simple data model and ability to model disparate, abstract concepts has also led to its increasing use in knowledge management applications unrelated to semantic Web activity.

Linked data is a term used to describe a recommended best practice for exposing, sharing, and connecting pieces of data on the semantic Web. The practice emphasizes Web access to data using existing Web technologies such as URIs and HTTP. It also emphasizes links between related Web resources. Linked data is by definition in RDF.

Linked data breaks the document boundaries of the original Web by enabling information resources about any given object or concept from anywhere on the Web to be combined into more meaningful understandings of that object and its relation to other objects or concepts. Via a common representation (RDF) and common vocabularies (RDF schema) and interoperable tools and understandings, data from any location or provenance can now be combined. This link facility enables the entire Web to be treated as an interoperable knowledge base and creates the ability to learn new emergent knowledge from the combined information.

Zitgist (pronounced "zeitgeist") (http://www.zitgist.com) is an industry standards-compliant Semantic Web query service. Its goal is to help Web users locate data, information, and knowledge on the Web. Zitgist develops and deploys Web application and data interlinking services that facilitate creation, aggregation, conversion, publication, and exchange of structured data. The company's main platform is the Zitgist Linked Data Server, accessed via the Zitgist Browser and Query Builder. zLinks is the client-side complement to the company's server-side technologies and services. The real work of zLinks comes through its access to the remote and free Zitgist Linked Data Servers. These Zitgist servers are the place where the heavy lifting of relating and finding new relevant information is done. An animated "working" icon appears while these additional related information and links are assembled. To learn more, check this blog post for more information: Blogs, Wordpress, Zitgist and the Semantic Web. The popup also has links to further FAQs and information regarding the zLinks tool.