My site weight was over 40,000 when I signed up. It's quite a large site so I'm pretty sure that's accurate (I have smaller sites that are proportionately smaller). However, I logged in the other day and now my base weight is 12,000!! Wtf happened. My indexed pages on google is still about the same count, I didn't have any referrals at all so It has nothing to do with that... Any ideas?
Like I said to you over MSN, just wait it out, Google might be updating your site, making some little changes... Be patient, it should blow over.