What about a location based service that makes discovering people? Like discovercircle.com?
Is there a future for location based services? What's are the current trends?
The problem with location based services is they require effort and if you don't reward that effort or reward it half-assed then it will just get old and eventually people will stop using it. That's what happened to Foursquare I do believe.
As it has been pointed out, location aware is the future. Your phone does the work for you, you don't need to open an app the app alerts you when a predetermined action or event triggers an alert. "Alert me when a train that stops at my desired stop is in the area between 5.30pm and 6.30pm", etc.
But there is also software that uses occasional location lookups, or data from other applications that use such lookups, and it's not necessarily in real time, and it does so in ways aren't necessarily user initated. It's data which can be gps but also wifi or even cell phone tower based, or even from other apps like navigation software) to do things like figure out generally where you are, give you dining suggestions, tell you about local events etc. When your weather app updates with the local weather, it's probably on some schedule, but it does a gps lookup every few hours. Same thing.
When Google Now figures out where you live and where you work using an occasional gps lookup/results from your google maps searches, etc, it's not a real time thing, but it is using location. I believe the iphone lets you set location based reminders. That's also location aware.
It's also rich interesting data. And since it isn't always on, it doesn't drain your battery.
Now either google, or someone with such data, is going to build an app that lets you opt in to sharing information about your general location, combined with data on your interests, to do some really cool things.
Also, It's not something I know too much about, but I understand that there are a lot of location based gay dating/hookup apps that are doing well. Better then some straight ones, especially if you take into account the smaller target audience.