This plugin adds to the signup page of WordPress MU a checkbox for TOS and/or a privacy policy.
Track referrals with Booking Calendar
Track your AffiliateWP referrals using s2Member Pro Coupon Codes
Add an "Agree to terms" check box on login, registration, or comment forms. Works with BuddyPress, bbPress and MultiSite.
Allow multiple user accounts to be created, registered, and updated having the same email address.
Prevent people from registering with emails that contain a subdomain to help reduce spam.
The ultimate plugin and service to stop and kill splogs in WordPress Multisite and BuddyPress, from WPMU DEV.
An easy way to place a Aweber form on your Wordpress site.
The #1 AWeber plugin to get more email subscribers. Easily add AWeber sign-up forms as popup, embedded widget or sticky top bar.
Botosub is the simple and effective tool for sending newsletters from Facebook and increasing your Facebook users.
Add a "Member Type" option to the BuddyPress registration form.
Logs the IP of the user when they register a new account. View the signup IP by going to the Users menu or by editing that user.
CalculatieTool.com signup and contact form.
Convert visitors to subscribers with targeted pop-ups, sideboxes, bars and inlines. Works with MailChimp, ConvertKit, AWeber, GetResponse & others
Simple create an event with guestlist and signup.
Provides Action Network (actionnetwork.org) action embed codes as shortcodes and a calendar and signup widget
The official Constant Contact plugin adds a contact form to your WordPress site to quickly capture information from visitors.
The DiloBox Subscription plugin allows you to quickly and easily add a signup form for your DiloBox list as a widget on your WordPress site.
It's signin extension from AA Production House.
An addon for the Affiliates Manager plugin to sign up affiliates to your Mad Mimi list