Sparks looks like the preemptive avenue for sponsored content. Reminds me of an AOL suggested content sinkhole. It's an insult, really. At least back when people were dialing up there wasn't much in the form of federated content so it was in AOL's interest to prime the customer with bland reading matter to keep them interested. This Sparks thing, I dunno.
I think at this point since they have all the early adopters already locked in and providing feedback, they should think of suspending any new signups until they have the circle matrix figured out, like Twitter did.