entr0py: Currently, all the sites I regularly play at use an 8x8 board, as BrainKing does. I have played other sizes in the past, including 7x6; see here for a list of sites offering connect four.
(sakla) If you want to find an opponent with similar playing skills to your own look in the Ratings page of the type of game you want and find a player with a similar BKR. (pauloaguia) (Bütün ipuçlarını göster)