Facebook has recently changed its chat interface to allow more selective filtering. Still, there are details to which you should pay attention, lest you accidentally reveal yourself to the very people from whom you’re trying to hide.
Facebook lets you use its Friend Lists feature to set who can see you when you’re online. When you pop open the chat window, by clicking the Chat tab nestled at the lower right of the page, it shows you which of your friends are also signed into chat. Look at the top of this list. You’ll see a list of your Friend Lists, if you’ve created any, plus another entry, Other Friends.
To hide from specific members, go to your Facebook home page. Click Friends in the upper left corner. Facebook will show a list of all your friends. In the upper right of the page is a button, “+ Create a List.” Click that. Facebook will pop up a dialog box that lets you select specific friends, either by clicking their profile images or by typing names into a search box. Add the people you don’t want to see you, and give the list a name, for example Hide on Chat. Click the Create List button to save it.
Then, go back to the Chat window and click Go Offline, then Go Online. Your new list will appear at the top of your list of visible friends. To the right of its name there’s an icon that represents a toggle switch from some electronic gadget. Mouse over it, and up will pop a label that says Go Offline. Click the toggle – you can’t drag it as if it were a real switch – and Facebook will hide you from the friends on your Hide on Chat list.
But there’s a trick: If you have a friend on two lists, one of which is set to online and the other set to offline, Facebook will make you online for that friend. To hide from them, you’ll need to either remove them from any lists you make visible, or to turn those other lists off as well.