DCI Certified Judge & Goth/Industrial/EBM/Indie/Alternative/80's-Wave DJDJ VortexDCI Certified Judge since July 13, 2013
DCI #5209514320My Wife's Makeup Artist Page <-- cool stuff - check it out
702.68a Poisonous is a triggered ability. “Poisonous N” means “Whenever this creature deals combat damage to a player, that player gets N poison counters.” (For information about poison counters, see rule 104.3d.)
702.68b If a creature has multiple instances of poisonous, each triggers separately.
Infect is different because it's a replacement effect.
119.3. Damage may have one or more of the following results, depending on whether the recipient of the damage is a player or permanent, the characteristics of the damage’s source, and the characteristics of the damage’s recipient (if it’s a permanent).119.3a Damage dealt to a player by a source without infect causes that player to lose that much life.119.3b Damage dealt to a player by a source with infect causes that player to get that many poison counters.119.3c Damage dealt to a planeswalker causes that many loyalty counters to be removed from that planeswalker.119.3d Damage dealt to a creature by a source with wither and/or infect causes that many -1/-1 counters to be put on that creature. 119.3e Damage dealt to a creature by a source with neither wither nor infect causes that much damage to be marked on that creature.119.3f Damage dealt by a source with lifelink causes that source’s controller to gain that much life, in addition to the damage’s other results.