You can update supporting social network locations by adding an extra bit to the end of your messages.
For example, you post: "I'm back home! @l home" - (thats a lowercase L)
This would update your locations to "home."
For Brightkite, we will try to use your placemarks first by searching for the location you post. If no placemarks are found, we will then do a general search for a geographical match. We will check you in to that location before posting your message.
Services that currently support location updating are Brightkite, Jaiku, Twitter and Rejaw.
Note: Everything after the @l is considered to be the location. If you are just updating your location, be sure not to include anything other than the location information. For example: "@l home" or "@l 74105" and not "@l hanging out at Adam's."
See Also: Posting Methods | Ways To Post Updates