Unfortunately, the most solid answer i can give is "it depends". It depends on the mix of personalities. If you have a couple people who are more quiet, and observatory in their habits, then 7 could work out fantastically! If you have 6 people who talk over others, or worse, don't talk at all while one person does his bacon-impersonation with the spotlight; it could be trouble. But i've had 7 people in a party, and it was great. Which should be even more amazing because it was an online game! In a game where all the people know each other, or at least have mutual acquaintances? Should theoretically be even smoother. Personally, my magic number is 6. Not sure why, but i know it is.