There were nice explanations how it is supposed to work, but the problem is that people out there can not manage that amount of bugs. It is possible, that for some core packages, they manage to do the job. However most bug reports will probably go to some leaf packages, which are not that important, but lot of people use them.
I started to interest in bugs in Ubuntu when I noticed that there is some huge number of bugs linked on phpMyAdmin's PTS page. There was something like 50 too much bugs. After quick look I could see that most of them are duplicates. After little fight with ajaxy interface, I even managed to mark most of them as duplicates and fix it in Debian package. But as somebody with no knowledge of Ubuntu (and not willing to learn internals of yet another distribution, I think Debian and OpenSUSE is enough), I really have no idea what could be done to push some bug fix to existing release. So once some Ubuntu release (The Lucid Lynx in this case) got new version, I marked the bug as fixed. This is probably not that nice to users, but somebody from Ubuntu community should take care of them.
Off-topic PS: If anybody is interested in Google Wave invitations, just write me an email, I currently have 15 without any use.