Something new from Twitter as they have plans to leverage location a little more.
You can choose to add a location to your Tweets using Twitter for Android, Twitter for iOS, twitter.com or other mobile applications. For example: To give additional location context to your Tweet, you can add a general location label such as “SoMa, San Francisco.” In select locations, on Twitter for iOS and Twitter for Android, you may also label your Tweet with the name of a specific business, landmark, or other point of interest. These locations are provided by Foursquare.
If you are using Twitter for Android or Twitter for iOS, the Tweet will also include your precise location (e.g., the coordinates of the street intersection where you Tweeted) in addition to the location label you select.
— Twitter (@twitter) March 23, 2015