Avatar thumbnails and caching
There seem to be two problems with avatars: They don't use thumbnails, so if someone uploads a 800x600 image, it gets loaded each time in full size, and only resized in the browser, which looks ugly.
To make matters worse, either caching isn't properly configured or doesn't work, so whenever I go to a forum overview page, all the sometimes really big images are fully reloaded.
Fixing that should reduce both loads on the Zoho servers and provide better client performance.