Apperceptive, the little engine that runs a large chunk of the professional blogosphere, gets a nice shout-out from Talking Points Memo's Josh Marshall.
One other point I should note: because of our size and resources, we've never been able to field close to the hardware resources behind the site as would be called for with the scale of traffic we get (to give you a sense, we now regularly get traffic equal to what we got on election night 2006, and almost four times what we got on election night 2004). That's required some custom tinkering to keep our blog train from going off the server rails. Now, we've gotten some nice praise recently for the stuff our team has published at TPM. But literally none of it would be possible without the engine the folks at Apperceptive have built for us that keeps the words streaming off our keyboards on to your computer screens.