Twitter has officially turned on geo-location options for users who like to tweet where they are.

The new service, which is rolling out across all users, will let you set whether or not you want people to see where you are twittering from if you tweet from the Twitter website.

Set as off by default Twitter admits that not everyone will want the new feature:

"Not everyone wants to add their current location to a tweet so this feature is off by default and must be activated to use", says one of the founders, Biz Stone, in a blog post.

The social-networking site is hoping that by tweeting your location it will allow them and you to show people where you are:

"Let’s say I’m at my office and I hear a loud boom. It sounded serious, so I search Twitter for “boom.” Among the first results could be someone who tweeted “Boom go the fireworks!” This could be anywhere in the world. However, if that person had activated the new tweet location feature then the neighborhood data under the tweet would read, SoMa".