The Foursquare app for Android has been updated to bring back an old feature called Nearby Friends. As you might expect, it showcases which of your friends have checked in nearby recently, and what they think about the locations you've been checking into. All you have to do is scroll all the way to the top of your news stream, and use that tab selection bar that pops up at the bottom.
Though it's only really the one feature (in addition to the usual performance tweaks), it's a pretty significant one, and those that are active on the network will be happy to see Nearby Friends again.
How often do you check in to locations using Foursquare? Do you have a lot of friends on there from out of town? Has Facebook proven to be more far-reaching, or do you see all location check-ins as excessive and useless information to share?