If it's the latter and anyone can play it could be interesting to have a long list of affilate blogs at the left, and show their current headlines in mouse-over drop-downs. That would allow quicker access to other sites, more of an overview of what's happening out there, and also more of a networky sense of wider involvement.

If you try to show titles and headlines without drop-downs, if the available space only allows two or three headline lists and the network grows, you're going to get an increasingly small slice of what's happening out there.

Although I suppose it could be a combination of both, with your favourite two or three sites shows in full and drop downs for the rest.