So this description will be as descriptive as this can get.
This plugin is known as SimpleTimeStamp. AS you have probably guessed it, yes its a timestamp plugin for your bukkit server that relays info to your MySQL database. ====
=== Features: ===
Injects online = 1 when player is online on MySQL
When player leaves, injects online = 0 in MySQL
Provides Date/Time of when player joined or leaves the server
All data is kept in check by UUID, name changes will not affect this plugin from doing its job.
This is great for keeping track of players for server admins as well, if you wanted to modify the code and add more stuff. Maybe make a mobile interface through web design etc and link stuff.