1) old friends and acquaintances that you've seen in the past and that you know haven't been on since then are gone...
2) blocks that your alternate accounts live in that appear populous and active are SUDDENLY only populated by two other people other than your alter account.
3) Your primary account is practically sitting around in the 'hood staff meeting house, in 3D, with his avatar's thumb up his avatar's ass all alone for an hour waiting for a weekly meeting that is more and more likely not going to happen....
it happened last week too but the difference is that I was late by mistake.