You can now invite a friend via steam!
1. Open "Online Game" and create a room. (with or without a password)
2. Scroll through your list of friends and click on the invite button next to the friend you want to invite.
3. your friend will have to open the steam chat to accept the invite.
4. back in BAO the game will automatically connect your friend to your room!
Easy invite system introduced!
Source: Steam Community (opens in a new tab)