Before reporting a problem, please check whether your question is answered by the FAQ linked to from the application's "Help" menu. (If you're unable to start the application, the FAQs are linked to from the applications' web pages.)
We're working on a proper public bug database, but at the moment, you should use "Report a Problem" or "Get Help Online..." from the application's "Help" menu if you're able.
If you're not able to report a problem from within the application (because you're having trouble starting the application, for example), mail our mailing list at . You'll get an automated reply telling you that your message is awaiting moderation. Once a moderator verifies that you're not a spambot, you'll be added to the whitelist and subsequent mails won't be delayed.
Remember to tell us the application (and version), the OS (and version), the architecture (x86, x86-64, PowerPC) — the "Report a Problem" menu item automatically encodes all this information in the subject line.
A good bug report usually answers all of the following questions: What did you do? What happened? What did you expect would happen? If you know how to make this happen every time, give us the exact steps; we might not be able to guess. You might also want to justify your expectation by telling us which different application or earlier version of our application does what you expected. Screenshots are often a big help when something looks wrong.