Private updates, including private-to-groups, private within a site, and private to followers only. Conversation mode in streams. Microapps can post different types of activities to timelines, with interaction. Events, bookmarks, Q&A, blogs, and polls. A new 3-column layout in the 'neo' theme by default. Alphabetical, searchable user and group directories. Better IM support with the addition of AIM, IRC, and MSN. Twitter-like lists. Subscription to searches. Subscription to tags. Extended profiles for private, enterprise sites. Sites are private by default. Daily email summaries. An automated upgrade script.
