Foursquare recently announced that they're splitting in two. They're moving the location sharing feature to a new app called Swarm. I've been a fairly loyal Foursquare user for quite some time. And when I think back to why I use it and why I've stayed loyal, I'd say it's a few things (in order):

Their search and discovery is really good. It's incredibly useful when I'm in an area I don't know well and random searches like "free wi-fi" or "cappuccino" are really effective. And their GPS is extremely accurate.
Foursquare records a history of where I've been. If I'm trying to remember a restaurant that I really enjoyed it's great to be able to look back at my history when I can't remember its name.
The gaming component is fun. Their UI/UX is absolutely phenomenal. I have to admit it's pretty satisfying when you check-in.

The one thing I don't use Foursquare for is location sharing. I don't have a large network on Foursquare and I'm uninterested in sharing my location with large groups of people. That said, there are lots and lots of people that love to share their location with the world. But that market was quickly swooped up by Facebook a while back when they released the exact same feature. So for me there isn't much value to Swarm.

I recognize I'm a sample size of one, but all of this makes me wonder if Foursquare unbundled because they wanted to create two really valuable, standalone apps. Or if the move was more of a spin-off or divestiture of a less valuable and less promising feature (location sharing). I'm not sure. But it will be interesting to see what comes of Foursquare and Swarm as mobile search, discovery and location sharing evolves.