I'll probably post to my blog with the statistics and comments about the reddit approach to advertising. I don't think much of the "buy a fraction of a day's traffic, but we're not going to tell you what fraction you're getting" approach, for one thing...
Experiment day is Thursday, so I'll probably have useful numbers early next week.
Assuming I write such a post, I'll submit it to both HN and Reddit. (And given how these things tend to work, I'll probably get more traffic from Reddit going to the blog post about advertising on Reddit than I get from the advertising itself...)
Good work. For cheap stuff like this, you need to act right away to get data. Thinking doesn't really do anything. I hardly know anything about A/B testing (except what I read here), but I don't think you need to let this test stop you from other tests (just create different landing pages, I think.) You mentioned elsewhere that you were going to wait 'till this experiment ended to start another. Don't delay, do it now.
EDIT: Ok, finished thinking. Let's see how much traffic $20 gets me.