Bukkit

This plugin utilizes Hidendra's plugin metrics system. the following information is collected and sent to mcstats.org unless opted out:

A unique identifier The server's version of Java Whether the server is in offline or online mode Plugin's version Server's version OS version/name and architecture core count for the CPU number of players online Metrics version Which Chat, Economy, and Permission hook is in use.

Opting out of this service can be done by editing plugins/Plugin Metrics/config.yml and changing opt-out to true.

None as of yet