Hi, I'm not sure if this is the right place to post bugs, but here goes:
I've have bad luck using mplayerplug-in to browse sites at
ytmnd.com. If you've never been to it, it's a site that contains pages of a specific format that contains three elements, all optional: a picture background (which might be animated), a background sound (wave or mp3), and big text in the center of the page, which fades into the background perspective-style. Mplayerplug-in plays the sound.
I don't have a reproducible bug for you, but hopefully you'll be able to find problems after browsing ytmnd.com for a few minutes. Typical usage would involve going to the site list, then middle clicking a link so that it opens into a new tab, and waiting for the tab to load, then closing the tab after observing whatever crude humour was within (don't judge me ;) ).
On Ubuntu, using Firefox 1.5, and the default plugin .so files from the apt repository, closing each tab happens abnormally slowly, and this happens consistently. On Gentoo, using mplayerplug-in 2.80 leads to crashes after browsing sites for a very short period of time. Perhap this is some kind of issue with linking, so I'm recompiling both firefox and mplayerplug-in. Nevertheless, someone might as well try looking at the site and browsing it for 10 minutes to see if they encounter any issues that they'd want to fix.