Among the new features is the idea of "checking in" to a local businesses, which will let you alert your Yelp friends that you're there--complete with a push notification. Yelp will also reward repeat visitors by denoting them as "regulars," with the most often visiting party getting a special badge.
That's not to say the idea of checking in is an unwelcome feature. It's giving businesses a new way to track Yelp user activity, something Yelp says could be encouraged through special rewards for its regular patrons. It's also containing Yelp's community within itself, and not just relying on external social networks like Twitter and Facebook, though as part of this release Yelp has added the option to blast out your check-ins to both.
Yelp is also doing Foursquare one better by putting your friends on a map--akin to Google's Latitude. This even works in Yelp's iPhone-only "monocle" mode, which uses the iPhone 3GS' camera to display restaurant locations (see a video of this). With the update it will now signal if a friend is at a certain location, as well as splitting the screen with a live map of the area.
Other new features include a way to invite people in your address book to Yelp. The app can also cross-reference your contact list to see if someone there is already on Yelp. Another big change is that the App now lets users edit all parts of their Yelp profile. In many ways, this signals that Yelp is finally getting comfortable with the fact that a good portion of its mobile users are likely accessing the site from just the app, and less so the main Yelp site.
Yelp's iPhone app continues to get the most attention of all its mobile apps, with the other platforms getting some of these cutting edge features a little later. A Yelp representative told CNET that the check-in system would be making its way onto other platforms in the near future, beginning first with Yelp's own site sometime next week. In the meantime, the company is working on getting the augmented reality monocle feature on Google's Android platform.