Dave Winer speculates about the FeedDemon/NewsGator thing:

Chris Pirillo has an interview with Nick Bradbury about the deal with Newsgator. I guess it's official now. I was briefed on the deal by Nick Bradbury a couple of days ago. I understand that the motivation was to allow FeedDemon to tie into the subscription-sharing network Newsgator is building. It seems inevitable that they'll buy a Mac news reader product, they would probably like to buy NetNewsWire, and it would be hard to imagine Brent wouldn't take a reasonable offer (I have no inside knowledge). This is venture capital at work, not sales revenue. I imagine that Newsgator will roll up with Feedburner (they share an investor), and Technorati may become part of this deal too. The goal? Get large enough to go public or merge with something going public (SixApart) or get bought by Microsoft.

If it actually goes like that, I'd expect a lot of infighting and chaos. Why? You'll have a lot of strong willed developers trying to build some kind of coherent, common client platform to go back to the shared NewsGator server. I already fully expect either FeedDemon or NewsGator (client) to disappear (and my money would be on FeedDemon).

Never mind what they said in the interview - there's venture money behind these guys, and the very first thing out of the money guys mouths will be something like "we only need one client - pick one, or merge them". I expect that the codebases aren't that similar, so an announced merge of the two would mean either lots of floundering, or the death of one product with a few of its features added to the other.