PJVisitorInfo is a simple concept of site visitors evidence.
It is parallel to Joomla JUser concept, as it concerns virtually all visitors regardless whether they are registered.
It consists of two InfoBase extension classes, PJVisitorInfo and PJVisitorTcpipInfo, and of a set of PJVisitorInfo functions.
The key feature is the DataProviderBase::CurrentVisitor() function which identifies the current visitor by registered user, cookie, mail address or creates new PJVisitorInfo instance if the identification failed.
Each time the extension calls for DataProviderBase::UpdatePJVisitorInfo($visitor), $visitor is stored along with his language, TCP/IP and current time.
See PJVisitorInfo APIs for details on PJVisitorInfo, PJVisitorTcpipInfo and DataProviderBase related functions.