Lots of people reading this are probably new bloggers - people who submitted to the Carnival of Vanities here on the 12th, or reading the one on the 19th (which I'm going to submit this too). If you're like me, you want to drive traffic to your site. Here's what I've concluded after many carnival submissions and two hostings.
Hosting the Carnival of Vanities had several perks - I got to read lots of posts on subjects I normally don't care about and would have glossed over if they had been in a carnival I merely read. It got me ~60 links by Technorati's count, and sent me up two categories in the Truth Laid Bear ecosystem. Those links included people saying lots of nice things about me, including that I had the best blog name ever (see banner). So if you're looking for traffic, hosting a CotV isn't a bad idea.
But these days, specialty carnivals are where its at. The Vanities just doesn't brings a limmited amount of traffic, this may be due to loss of interest among big-shot bloggers like Glenn Reynolds, who's only been intermittently linking to the carnival. Also, you're guarenteed to get readers interested in what you're writting on. This goes not only for submitting, but also hosting, assuming you host a topic you're interested in. When I hosted the Carnival of the Godless, it brought in about 300 visitors, and submissions to specialty carnivals have brought in about 100. Invariably, some, though not all, stay.
What carnivals are out there? Here's a list to start you off. There are regional carnivals, like the Tar Heel Tavern and my state's Carnival of the Badger. There are science carnivals, humor carnivals, medblogging carnivals, philosophy carnivals, and gun carnivals. There are carnivals for Christians, carnivals for atheists, and one for both (and anyone else who has an opinion on religion - that means you!) I bring the last one up because there's some lack of submissions on the theist side, any theist bloggers reading this, please consider submitting.
Of course, I don't have time to list them all. I don't even know them all, the is just most of the ones I have at least a passing aquaintence with. No guarentee you're experience with them will be the same as mine. The experience of involvement with a carnival may very well vary as much as the carnival subjects themselves. But involvement is something I strongly recommend for anyone who wants to break in to the bloggosphere.
UPDATE: Instapundit just linked to the CotV here, so it's no longer accurate to say he's stopped. There had been a lull for more than a week, though. Hopefully for the sake of the Carnival he'll continue to promote it.