Business review service Yelp will update its mobile apps soon to include a feature called "check-ins," a feature similar to one that several smaller location-based social networks have built their businesses around. This according to several other blogs that were given early access to the feature - blogs that, co-incidentally, are less likely to mention complaints about Yelp, like that it is hated by many business owners, is believed by some to be full of extortionists, and is believed by many to be filled with self-absorbed, chronically snide hipsters.

Those common criticisms aside, Yelp is pretty awesome and the addition of check-ins could make it even more awesome still. Or it could be really annoying. It's hard to say for sure, but it's definitely going to be a big deal.

Only Apple knows for sure when the update will be live for the Yelp iPhone app but when it is, here's what it will look like:

  • You'll be able to click a button to check in when you're physically present at a location listed on Yelp.

  • You'll get a badge marking you as a regular when you check in regularly from one location and your review will reflect that status.

  • You'll be able to get an iPhone push notification when a friend of yours from the site checks in someplace.

  • Check-in data will eventually be available on the website in addition to the mobile application
  • .

What does this mean? It means that many more people around the world will be able to enjoy the very cool ideas that smart little services like Foursquare and Gowalla have come up with but have had limited userbases with which to score network effects outside of a few large cities

It means you'll want to launch the Yelp iPhone app more often and that the app will be pestering you with friends' check-ins, reminding you to pay attention to Yelp. It means you'll be more likely to make friends on Yelp. It means you'll be walking down the street in your town, find out a friend is nearby and you'll change your plans in order to go hang out with them.

If implemented well, it's probably going to be a whole lot of fun. A good implementation might include shut-off times for push notifications and intelligent integration of your friends, favorite places and other information.

What are the smaller companies in this space going to do? That's a tough call. Most social networking activities are a lot more enjoyable if a larger number of people - and a larger number of your friends in particular - are participating. That means Yelp.

There may be important cultural differences, though, that leave space in a larger market for smaller players. Yelp may remain dominated by a certain crowd that's considered distasteful (perhaps so tasteful it's distasteful) by enough other people to make alternatives economically viable.

We've got different TV and radio networks for people with different tastes today, might we not have different location-based social networks for people with different tastes tomorrow?

We're about to find out, because leveraging location data on the mobile phone is about to become a much more common thing to do.