http://ip-check.info/?lang=en does a pretty thorough anonymity test inc java, flash, cookies etc.
https://www.browserleaks.com/ does a very comprehensive browser IP leak test
You can be tracked and monitored by your browser agent. Panopticlick also gives a insight into how uniqe or not your browser is: https://panopticlick.eff.org/
Find information about your IP: http://www.ip-score.com/