Ask HN: What are the best ad services for low traffic sites?

I'd like to know some of the options for ad services -- specifically, those that provide ads so I can generate a little revenue from a Website (preferably at least enough to pay for the hosting). I'm looking for things in the same vein as Google AdSense. What are the options? What do the hackers who frequent Hacker News use?

Note that:

1. Services that don't work until some advertiser specifically picks out a given site don't work so well for fairly low-traffic sites, because nobody will ever want to spend money to advertise there.

2. I'm not interested in the kinds of ad services that essentially require me to either write ad copy as site content or to post ad copy written by someone else on the site and pass it off as my own words.