I currently use MarsEdit for my Blogs, but I see that it has the potential to be used to edit practically anything in IBM Connections because its primary API is AtomPub. At a minimum, I would LOVE it if I could edit Wikis in MarsEdit because that would be a huge benefit to my workflow with local saves until I'm ready to release Wiki updates.
IBM connections has many different "applications", and if ME could be configured to connect to a "site" rather than an individual Blog, I would be able to use it as my primary IBM Connections Editor. This would make it unique among all software that I am aware of on OS X, Windows, and Linux. The only thing that even comes close is the Mobile Connections application developed and released by IBM.
You can read all about the Connections APIs at the following link:http://www-10.lotus.com/ldd/lcwiki.nsf/dx/IBM_Connections_API_overview_ic301