I can see this as similar. There's something pathetic about being the first Twitter follower, or the 6th "Like", and something scary, particularly for a local business, about vouching for something you're not really 100% sure on. Writing the 4th 5 star review is a lot easier than the 1st one, and it's easy, and more anonymous, to be the 45th Like.
I don't support these services, and think we need good heuristics to stop them, but I can totally see why even an early influx of a few fake followers and reviews would "seed the pot", and be worth way more to a business's eventual health than $20-40.