It’s amazing how often technology comes back to food. Apps like Yelp let people review what they’re eating; Evernote Food helps people remember what they ate; and RunKeeper or Fitbit aim to get the overeating-induced flabby bits under control. This parody video, which claims that people only use the iPhone to take pictures of their food, is probably more accurate than most would care to admit.

LocalSpin, an iPhone app that launched this week, is another food-centric app. (Thank goodness, because otherwise that lead wouldn’t have made any sense.) The app was built to help New Yorkers get an idea of what they should do or where they should eat in their neighborhood. No easy feat, given the size of the five boroughs and the diversity of each neighborhood, where one can hear five different languages and find eight different shops serving a variety of cuisine.

The service is built on top of Foursquare’s location data, and currently relies fairly heavily on users connecting their Facebook accounts to see what their friends recommend in the area. Though this may help with the “local” aspect, if your friends live in the same neighborhood or if you’re heading to their part of town, it puts a damper on LocalSpin’s usefulness for someone new to the area. Users will download and launch LocalSpin to find somewhere to eat, not to be reminded of the fact that they have no friends, and right now the app may as well sing “One Is the Loneliest Number” on first launch. There is an “everyone” option available, but even that section seemed to be relatively sparse (compared to other apps) during my testing. The users – and the data that comes with them – simply aren’t here yet.

This isn’t through any fault on LocalSpin’s part – new services, pretty much by definition, tend not to launch with a large number of users. Unfortunately, just as LocalSpin attempts to convince users that it can help them navigate their crowded neighborhoods, those same users have access to a dizzying number of other options. Yelp comes to mind, as does Foursquare’s  Explore option, and a user might go really crazy and just ask their Facebook friends or a real, living person what usually tickles their fancy. Which is all to say, “Why should I use LocalSpin instead of X” will be the first question on every prospective users’ mind.

John Myers, one of LocalSpin’s cofounders, says that one of LocalSpin’s value-adds is the brevity of user’s recommendations. Users have to limit their reviews to 140 characters – or, basically, a Tweet.

Instead of having “all encompassing” reviews, Myers says, LocalSpin’s focus is on giving one really good reason to eat somewhere. Relying on Facebook friends also means that users won’t be subjected to the often vile reviews that Yelp-ers tend to spew across a restaurant, somewhat mitigating the “the Internet is a dark, ruthless place” factor.

So, why LocalSpin? Right now that question is hard to answer – as we’ve established, the service is a bit of a ghost town (at least for someone that only just recently moved to New York). But that may not be an issue forever. LocalSpin is knowingly entering a crowded market, and convincing a meaningful number of users to stop Yelping (or whatever the proper verb is) is going to be an uphill battle.

If more people sign up, however, LocalSpin is in a decent position to answer the “what should we eat?” question. Building on top of other platforms is a risky proposition – ask a few Twitter developers – but it shows that LocalSpin is focusing on the right thing: people. Potential users are already on Facebook and probably already on Foursquare, so why not mash the two together and get some grub?