When people like DeLong, and Volokh, and Schmitt and Cole are sharing their knowledge, you don't need to waste time getting a second-hand digest.
But some of us will always want the second-hand digest. As wonderfully and as clearly as the delongs and volokhs present their area of expertise, most people do not want to struggle through the complex issues on their own.
Political identity is closer to team sports identification. People like Goldberg are giving the rallying cry for their side, not "debating" or engaging with the reality based community.
I love the weblog world, and I think it has the potential to change many things. But I don't think it's going to displace empty-headed jingoism in partisan rhetoric.
Displace? Showcase it is more like it.