I don’t know about “me too” types of bug replies, but before everyone goes to the bug database and starts saying “me too”, “this affects me”, “please fix this ASAP”, “I won’t use MySQL 5.1 till this is fixed”, I wonder if this will cause more harm (i.e. more bug spam for the developer, and all those subscribed to it) than good.
Take one of my favourite worklogs – WL#148 (to implement engine independent foreign keys). Not only can you tag it, you can also comment on it (like a bug report), you can subscribe to it (watch it) and in the event you felt like a “me too”, you just login, and vote!
Lots of bug tracking systems have voting. I remember this being implemented on the OpenOffice.org system (IssueZilla) a few years back, and its definitely proven to be useful. Maybe this is a feature request, for our bugs system?