About 58 million people worldwide use Twitter
The micro-blogging website Twitter is buying the location tracking start-up Mixer Labs for an undisclosed sum.
Mixer Labs, founded by two former Google employees, makes an application for Twitter called GeoAPI.
Twitter chief executive Evan Williams said the deal would allow Twitter users to show people where they are when they post updates to the site.
The application will also allow users to search where an event is happening, the firm said.
On the company's blog, a statement said: "We want to know what's happening, and more precisely, where is it happening.
"As a dramatic example, twittering 'Earthquake!' alone is not as informative as 'Earthquake!' coupled with your current location".
Twitter is a social networking site in which users write messages of no more than 140 characters.
An estimated 58 million people use Twitter around the world.