Carnival of "X" is a recent meme in the blogosphere that is essentially a group of topical blogs taking turns, on a weekly basis, identifying and aggregating the "best of the best" of blog posts on a particular topic....
For example, quite a well established carnival is the Carnival of Moblists, which is a group of blogs focused on the mobile phone industry.
So why bring it up here? Well check out the carnival of marketing started by okdork that is hosted this week at BrainsOnFire
And here's a list of upcoming sites that are hosting the carnival of marketing:
4/16/2006 devin.reams at gmail.com Devin Reams
4/23/2006 bob at firesomeonetoday.com Fire Someone Today
4/30/2006 david at rnd2reinvent.com Market Ventures
5/7/2006 douglas.davidoff at imaginellc.com The Fast Growth Blog
5/14/2006 weinreich at social-marketing.com Spare Change
5/21/2006 eric at marketingmonger.com Marketing Monger
5/28/2006 Lbodine at lawmarketing.com Law Marketing
6/4/2006 howeswr at aol.com Planning Blog
IMHO the carnival of "X" is a wonderful addition to the blogosphere and enables smaller, niche blogs to engage in some friendly co-opetition, helping focus on topical content and getting out of the A-List rat race :-)
Oh, and consider yourselves on the cutting edge, there still trying to figure out how to define blog carnivals on wikipedia