Greg Reinacker: It's been a while in coming...but the NewsGator Online API - the next major piece of the NewsGator platform roadmap - is now online and ready to use.
http://www.rassoc.com/gregr/weblog/archive.aspx?post=772
Randy: This is one of the best API implementations I've seen. They have clients (NewsGator Outlook and FeedDemon) that are already using it.