Based on the poll results so far, my experience isn't that atypical.
Most of the folks who play co-op play with mostly the same people, and only a handful play with whomever they can find--and all the folks who play with "randomes" also play solitaire a fair amount.
Lots of folks play solitaire, but few play exclusively solitaire.
I'm assuming that people who play co-op mostly play the game with friends they knew before, as opposed to people they've just met online and now play with regularly, but that's an assumption. That speaks to the social aspect of the co-op game, and also suggests that AI Wars sales might rely even more on word-of-mouth (verbal or virtual) than other games.
That's probably not a surprise to anybody here, but I wonder how representative it is of folks who bought AI Wars in general? No way to know, I guess, but we probably all have opinions...