For those keeping score at home, the problem with AIM in Adium 1.0 beta stemmed from overexcitedness on the beta's part. AIM imposes a "rate limit" which prevents clients from sending too much data too quickly. We were effectively ignoring that rate limit during the sign on process.

That was well and good (sic), except that an AIM server upgrade, unrelated to Adium or any other third party client, occurred on Thursday of this past week. That upgrade included stricter rate limiting requirements, which pushed Adium 1.0 beta over the edge. After the upgrade, users whose buddy lists required significant information requests during sign on -- large number of buddies, many away buddies with away messages, many buddies with buddy icons -- were summarily kicked during sign on.

We've fixed the problem for 1.0b9, which will be available in the next 24 hours. :)