I'm writing up my PhD thesis at the moment, and found myself having to update the opening paragraph of page 1 (you know, the part where I say how incredibly relevant my research is). The previous version, from my transfer thesis written in 2012, went like this:
Mobile location services have been a topic of considerable interest in recent years, both in industry and academia. In industry, software applications (or apps) with location-based components enjoy widespread use. This is evidenced, for example, by the 20 million active users who opt to check in (i.e., share their current location with friends) on Foursquare , the 50 million users who search for local services on Yelp when out and about, and the increasing number who electronically hail a taxi in Uber in 11 cities (up from 1 city in 2011), which they can then watch arrive at their location on a real-time map.
In updating this paragraph, I found that the statistics reflecting 2013's progress by mobile location services are as follows: Foursquare grew from 20 to 30 million users, Yelp grew from 50 million to 100 million users, and Uber is now in 66 cities (up from 11 cities in 2012).
From this small sample of progress, it seems that there is still a lot of growth in location-based services, especially ones involving crowdsourcing of physical tasks (e.g., Uber, TaskRabbit, Gigwalk).