Essentially, Aqua Taskforce is a bug tracking site that’s confined to OS X user interface quirks and annoyances, rather than full-on bugs. You register and login, then you can post your Mac gripes for all to see, vote for/against, and comment on. Sometimes the discussions get quite lively, as one person’s meat is often another’s poison (as evidenced by the comments in my recent 10 usability lows of Mac OS X post).
My favourites include List the apps that prevents unmounting (how nice would that be!), Dialog windows lack keyboard shortcuts and tabbing (by default), and the old classic, No Cut option in the Finder.
On the one hand, the idea seems rather pointless as presumably no Apple engineers are seriously looking at the site for bugs to fix (though the site’s creator reckons that various Microsoft types are scanning Aero Taskforce, so you never know). Then again, because Apple isn’t the most open of companies when it comes to feedback, it’s nice for people to be able to publicly share their Mac UI grievances and feel a bit of love from like-minded users. It’ll be interesting to see if the site pans out over the coming months.