I got a ping recently about BlogUpp, a reciprocal advertising network for blogs. The concept is this: you submit your blog to the service, and it gets advertised to other BlogUpp users in proportion to the number of BlogUpp ad units you serve on your own site. And it's free.
It's not a bad setup if you don't mind running ads for your competitors. To be clear, though: you shouldn't, because they'll all be running ads for you in return. This isn't a zero-sum game. A user who is interested in the topics you're covering is not likely to abandon your site when they link over to another. A more engaged audience in any field is good for almost everyone (except perhaps for sites with large readerships that are coasting on their reputations).
BlogUpp makes money by reserving 10 percent of the ad spots for itself and monetizing them through Google. You'll never see that money, though. For its subscribers, BlogUpp pays only in traffic.
The service attempts to display on your site only links to blogs in your field. It does that by comparing RSS feeds of all its subscribers. It looks like it does a decent job; judge for yourself in the live demo spot embedded in this post. Update: Maybe not so much, at least at launch. Your results may be different from what I am seeing right now on my screen, and I hope they are: I get an ad for BlogUpp itself and another spot for a blog in a language I can't even identify. We'll see how well the blog-matching technology works as the network grows.
What I like about the service is that it is unbelievably easy to sign up. There's no registration, which is highly unusual for a product like this. You just give the service your blog URL and it spits back code you can embed in your site.
One downside, though, is that the service doesn't yet offer any analytics to you: What traffic are you getting from the network? From which sites in particular? Where are your users linking off to from your site? This is stuff that competitive bloggers obsess over, but there's none of it in this early version of BlogUpp. Also, you get no control of where your spots will appear or what spots appear on your site. The company does say it will filter out adult and illegal content, but it doesn't let you blacklist blogs you don't want to associate with.
Click-through on the BlogUpp units might not be huge, but if you have the real estate on your site, it's worth experimenting with.