The show was a hit in syndication on FOX, but it moved to UPN for its 4th season, after which it was cancelled due to poor ratings.
In the whole four years the show was aired, we never fully see anybody's parents. We hear the twins' parents in Episode 6, and catch a glimpse of Shred's dad twice in Season 3.
'Michael Hayashida' joined the cast in the middle of the first season, as foreign exchange student Koichi. He stayed until the end of the season, when he disappeared, never to be mentioned again. Patty Gilbert also disappeared without an explanation before the beginning of the second season. Bruce Patman was the only character whose sudden disappearance was actually explained.
Only Cynthia and Brittany Daniel appear in all 88 episodes. Amy Danles, Michael Perl, and Harley Rodriguez are the only other cast members to appear in all four seasons.