I'm a product creator, and in attempt to track and stem my losses from piracy, I occasionally visit a bulletin board dedicated to piracy and piracy-for-profit; my products are regularly pirated and sold there.
When visiting, I often get intrusion alerts from Kaspersky, and I received one such today.
After I left the site and browsed elsewhere with the new FireFox 4 beta, a window popped up to indicate that a Thunderbird add-on for the beta was available, and offered to install it.
I accepted the installation.
A few minutes later, Thunderbird opened without my doing, and displayed an outbound email with the administrator of the bulletin board named as recipient. (I know the guy's email address, and he explicitly boasts of hiring hackers to penetrate sites so as to copy and sell the products he finds.)
So, have I been hacked, and if so, what should be the next step, security-wise?
(Note: Kaspersky regularly alerts me of intrusion attempts when visiting that guy's site, but never displays a record of them afterward.)
Thanks in advance for any suggestions.