How does app-store SEO work? I sell some apps on the app store, but I've never tried to market them (and have pretty anemic sales as a result).

Does SEO tend to be black hat (hire people to rate it?) or ad-driven?

i think it has more to do with having possible search terms as your app title

At a glance, for sure- there's a few where they didn't, but for the most part they did a solid job of it.

For the ones where they didn't, I'd guess (based on nothing but a glance) that they depended on cross-selling to get rank traffic, instead of search to get rank traffic.