Notice how for anyone who donates more than $5 they need to send them a CD with Diaspora on it. $25 gets them a t-shirt etc.
For 6k donors, they're going to spend ~$50-100k of the $200k they raised just meeting their commitments. Not to mention a huge amount of time dealing with the logistics.
Edit: Jesus, if you account for the fact that they promised 1 year hosted service, and 1 year phone support for anyone who donated more than $350, these guys are already underwater.
I think it's a appropriate response too. Wordpress does both hosted and open source, and by all accounts they're doing OK.
By "hosting" they mean 1 year of a Diaspora account on their server. So essentially that's 30/month for unlimited photo and text uploads to a walled garden site. I'm pretty sure they're fine.
Anyway, I believe the phone support is a much more serious liability.
1. You're paying for the infrastructure that the support volunteers need to do their job.
2. You receive value for it. If the answers help save you time and money, do you care what motivates the people providing them?
3. You and the volunteers are both supporting a broader effort.
There are plenty of organizations that rely on volunteers that also charge user fees to support their mission; any museum with a docents program, park guides, ushers at the symphony, schools that rely on PTA volunteers to cover unfunded positions. It's not exactly radical.
Also, founders' time, which is probably the most costly part.