Acitvator is a set of "event-condition-action". I.e. the activator is caused by a specific event (which it is subscribed), checks for certain conditions (flags) and performs some actions.

List of activators

Activator typeRelated event type
BLOCK_BREAKThe player destroys the block
BLOCK_CLICKControl the actions on the blocks
BUTTONClicking stone or wooden button
COMMANDExecute command by player
DAMAGEPlayer Damage
DAMAGE_BY_BLOCKPlayer Damage by Block
DAMAGE_BY_MOBPlayer Damage by Mob
DOOROpen (or close) the door
DROPEvent to throw objects by the player
ENTITY_CLICKRight click on the entity
EXECExecute activator (using command line or another activator)
FCT_CHANGEPlayer changing faction
FCT_CREATECreating new factions
FCT_DISBANDDisbanding new factions
FCT_RELATIONChanging relations between to factions
FLIGHTChanging flight mode
GAME_MODEChanging Gamemode
GODChanging God Mode
INVENTORY_CLICKControl on the actions with the inventory using the mouse or keys
ITEM_CLICKRight click holding specified item in hand
ITEM_CONSUMEConsume (eat or drink) specified item
ITEM_HELDPlayer changes the item in his hand
ITEM_HOLDHolding specified item in hand
ITEM_WEARWear specified item
JOINPlayer joining the server
LEVERPulling the lever
MESSAGEFound specified message in chat output (or in server console-input, or chat-input)
MOB_CLICKPlayer clicking mob
MOB_DAMAGEPlayer dealing damage to mob
MOB_KILLPlayer killing mob
PICKUP_ITEMEvent to pickup drops by the player
PLATEPressing (walking on) stone or wooden plate
PLAYER_DEATHPlayer death
PLAYER_RESPAWNPlayer respawn
PVP_KILLKill another player
QUITPlayer leaving the server
REGIONEntry and staying in WorldGuard region
REGION_ENTEREntry in WorldGuard region
REGION_LEAVELeave out WorldGuard region
SIGNClick sign
SNEAKChanging sneak mode
VARIABLEChanging ReActions variable value
WE_CHANGEEditing the world using the WorldEdit plugin
WE_SELECTION_REGIONSelecting a region using the WorldEdit plugin