Again, I don't think blogging about this will influence your A/B test, because your (future) customers and people reading your blog don't overlap very much (or at all).
But, I do think publishing the A/B test does influence the outcome if they do overlap.
You are talking about the $30 that you could get but miss the point: you might get some extra money but in the process corrupt the validity of your A/B test and make a bad decision afterwards, based on that result. Well, not that it matters anyhow, as I'm pretty sure you have actually decided already to stop doing the Java app.
I would like to have somebody that knows more about sociology and statistical surveys explain if what I am saying makes sense or not.
The point of the A/B test is that, once devised, it is purely statistics and the software (from here on in) will tell patio11 which of the two options to adopt.
> You are talking about the $30 that you could get but miss the point
I think you missed his: it's pretty unlikely that anyone on HN will do that.
Are you sure that only HN readers read the blog?
I'd be surprised if teachers didn't check out your blog before buying. Teachers "get" blogs, hell they LOVE blogs. They even get their students to blog (to build writing skills using peer interaction). Seems like the ones who are confident enough to go out and use your software may also be the ones who would check out the blog. Just a guess on my part, but at least keep an eye out for this.
"Several dozen HN users will go to the website, see which variation they get, clear their cookies until they get the right one, then pay me $30... and then cackle madly" is not a real worry.