Steam has been added to the available messengers you can list for yourself in your profile.
ID must be in one of the formats or it won't save;
- steam id: STEAM_0:X:XXXX
- http://steamcommunity.com/profiles/7656119XXXXXXXXXX (profile page url)
- steam community id: 7656119XXXXXXXXXX
When added you'll have a steam tab in your profile (yes I know the tab doesn't look right, it's on the fix list), a steam icon with the other messenger icons in the userbit and member searches.