The long list of changes is well documented in the past few code tours, but I wanted to highlight some of the more important differences that will hopefully be of benefit to everyone.
First off, there is a new account settings tab for keyboard and touchscreen shortcuts. There is already a great writeup from one of our accessibility experts explaining and promoting this feature, so I won't go into more detail here, except to say that it looks neat and you should check it out!
Secondly, it is no longer possible to list your AIM or Imzy username on your profile, because those services have shut down. However, we did add a field for including your LiveJournal username! (How did we go so long without anyone thinking to add that?)
Third, for our dedicated post-by-email users (you know who you are): you can now use "post-screenlevel" to change the screening level to something other than the default, and "post-security" to specify a comma-separated list of access groups to use. Related to this change, we no longer allow you to use commas when naming access filters, but if you already had 'em, we left 'em alone; it won't be a problem unless you want to use that particular feature.
Fourth, if you use the RSS/Atom feed of your journal as a crossposting source, and don't want to see the comment count info included in the crossposted content, you can now append "?no_comment_count=1" to the feed URL to make it go away. (These are the sorts of features we add in response to support requests, on the theory that if one person bothers to ask if something is possible, there are probably at least 10 others who would appreciate the feature but don't ask!)
Fifth (why am I enumerating these anyway?), we've updated the text you see when viewing your own profile, to more clearly indicate not only how many icons you have uploaded, but how many you currently can upload, including any bonus icon slots.
Next, you may notice that several parts of the site that accept email addresses as form input will more aggressively check for misspelled domain names. You should be able to override any incorrect complaints without too much trouble, and this will hopefully cut down on the number of requests for help we receive from accounts associated with invalid email addresses.
Penultimately, we have added several more sites to the whitelist we check for allowing embedded journal content. Instead of detailing them here, I'm in the process of creating a FAQ that will authoritatively list all of the currently allowed sites. I'll update this post when it's ready to go.
Finally, the long standing bug of community membership options failing to save when submitted should finally be fixed! Hurrah!
Thanks to everyone who helped with these and the myriad other little tweaks that go unsung, but not unnoticed. And if you're one of the people who reported a bug or requested a feature, give yourself a pat on the back, because you are a vital part of the process as well. Cheers!