I've been following Gnomedex via Twitter--a bunch of people I follow are there. Dave Winer just said, regarding Mahalo:

When someone gets up and gives a speech about a platform, my mind gets engaged about ways I can have fun or make money.

There's none of that with Mahalo. It's about Jason and his investors making money. Why should I care about that?

It's like the iPhone. Very limited opportunities for us to be creative.

From Here's what bothers me about Mahalo (Scripting News)
Referenced Fri Aug 10 2007 18:28:11 GMT-0600 (MDT)

Dave is making an excellent point here--maybe the most important point for anyone thinking they're making a platform play: it's not a platform if it's a walled garden. The fewer walls and barriers--the more ways to have fun and make money--the more accepted you'll be.