Player created and enforced game modes (as desribed by 'shnozlak').
Custom map: large center object and invisable barriers on all sides
custom map: two identical bases, each team gets one cant cross the center divide, starting weapons vary, no jetpack or rope (ususally)
Must collect a crate to attack, no starting weapons, usually played on purpose built maps, infinite rope.
Entire map filled with dirt, must tunnel to attack, sometimes you only get the exploding mole weapon and maybe a grandma.
(Bazooka and grenade) Worms stationary on special maps, no 1 or 5 second grenades, no straight shots with the bazooka.
get your 2 or 3 worms to the end of a maze first (made using custom map). No killing other worms
get your worms to the end of a maze using explosions from weapons without dying from the ensuing damage. No attacking other worms.
Amazingly no-one ever seemed to troll these games. The best thing about worm-net was the gameplay lent itself to fair play. If someone was being a dick the 2-6 other players would get pissed and turn on him, killing all his worms and only his worms untill he was removed from play. It was also considered bad etiquette to kill a player's last worm if they were losing, so even a really green new player would typically have fun. Worm-net was the most fun, fairest online multi-player environment ever.