Where do I ask for beta testers for a niche web app?

The guidelines are read, but I still haven’t got the slightest clue where one would go to ask for beta testers for a web application that most probably would interest users of this forum.

It’s a very targeted app, and I don’t think the “general public” will have much use for it either, so posting it in the general review section seems like a waste of everyones time.

It would be really cool to get some search engine marketers to test out this app, anyone know where to ask a specific group without breaking any guidelines?

The answer “nowhere” is better than no answer at all. Thanks!

After some more posts, it would likely be acceptable to post it in your signature.