(I know it's the 28th as I'm posting this, but the changes went live yesterday.)
- New site format. Site should be mobile-friendly and adjust itself to fit in whatever width of browser you're using. It should do this without dropping content (just pushing stuff in the sidebars to the bottom, converting some menus to drop-down lists, etc.) This layout will need tweaking to iron out all the wrinkles (it's hard to test mobile devices when your test site isn't accessible by mobile devices...)
- Comments no longer have titles. This is actually kind of annoying but it's part of the theme, and attempts to bring titles back were a theming disaster. There are still comments in forum replies, but those will be going away in the next update.
- WYSIWYG text editor has changed to tinymce. Seems to work better than the others ones I've tested.
- I had one report that the Mollom captcha has become horrible. I don't know what to do about that, because Mollom works really well when it comes to filtering out blogspam.