There are some things about it that are games-specific, such as the festival calendar and the sites that Promoter is crawling for press mentions. It could be expanded to non-game apps in the future, but I wanted to start with the area I have most expertise in.
The VAT pricing is due to the tax rules we have in Europe, but I can see that it adds noise to the price point. Monthly payment is something I'd want to add, but I wanted to keep it as simple as possible starting out.
For the average scores you enter the scores from the reviews to Promoter (e.g. 7 out of 10). Promoter will then calculate the average of all reviews.
Not sure what you mean with the Google+ joke? ;)