please check the post. But actually everything is good to promote your app, you have to try and see the result. The difficulty in promotion is that most of the times difficult to evaluate to ROI and it is a kind of weird thing for software engineer - you don't know if it works or not (except if you've got a mention in a major blog/newspaper). But mentions in major blogs or newspaper don't appear by magic, you have to make some noise about your product.
So You just want that your app is visible to everybody. If, by magic, everybody was aware of my apps I would sell 100,000 units in one day I think !
