Do you want to be online with your mates on Facebook, but appear offline with your work colleagues?

You can now do that by using Facebook's "friend lists" to filter your connections in the social networking site's chat application.

Apparently a much requested feature, the new chat function lets you go online with the instant messaging service, but only to certain people from previously composed, or new lists, created directly in the chat pane.

Facebook explains: "Alongside each list, you'll notice a green switch; when you turn off the switch, you'll be logging off of Chat for that list. Friends in lists that are switched off will not be able to see that you are online or chat with you, nor will you be able to see whether they are online".

Friends lists can also be used to filter your home page, send inbox messages and manage privacy settings.