Similar issue... I've been running a fresh install of Gloria for close to a week (not an upgrade from the RC) and haven't had any update notifications (other than the first set after you initially install.) Just now I changed mintUpdate preference to show me level 4 and 5 updates, and it STILL came back with no updates available. That's a little disconcerting.
Could one of the moderators reply if they've had any kind of updates over the past week? If they haven't, then I'll return to my state of blissfull ignorance.
If they (or anyone else) has, I guess I have some work to do to find out what's wrong.