MCB Stats collects statistics of users who access to the front part of wordpress, MCB Stast is capable of collecting the total amount of time a user spends in the different pages, this requires an important server load since it does insertions in the data base every X seconds of every connected user and opened page. Luckily this charge can be configured, the more seconds the less it loads, but also it will be less precise. Even if this is the best plugin’s potential, it also collects other statistics, like links users click, buttons, when they send forms or enter to a page, the logins and the log outs.