In fact, they're oddly static - the number of reviewed restaurants and stores has increased quite slowly for most cities, they haven't done a good job pushing into smaller markets.

Admittedly this is my anecdotal observation but i've been following yelp pretty closely since they launched and honestly up until the Google acquisition attempt, i was wondering if they were short on cash because they seem to spend so little energy on product/design/site and there seemed to be a bit of desperation in the whole 'yelpscam.com' accusations, which appear to be legitimate.