Twitter has announced that their tweets will now include the option to give longitude and latitude information along with the tweets. This will make it easier for users to see tweets from nearby locations acting like a filter. The option first became available in third party applications such as tweetDeck. This will soon launch directly on Twitter.com and the official mobile version of twitter. In order to make use of the services you will have to opt-in for privacy reasons. The location information will not keep stored indeffinately.