Craig Hockenberry on App Store reviews:

Some have suggested that buying the app should be a requirement before leaving a review. I agree, but this will not completely mitigate the need to vet content. A large percentage of applications are free: the trolls will just download before going on their merry way.

If all of this wasn’t depressing enough for developers, I’ll leave you with my biggest disappointment: reviews are a one way street. I’m not one to feed the trolls, but many of the reviews I’m seeing would benefit from a “Just try this…” or “We’re working on that…” type of response. There’s not even a link to our support on the reviews page.

I’ve found that the effect of having a single, centralized source for iPhone apps can be a two-edged sword. While it gives the developer much greater exposure with much less work, it also provides a single, centralized feedback forum, with a de facto community of users that can and will publicly praise or decry your work.