Map Hacking
A map hack allows a player or players to view the entire map rather than only their team's side. The team using a map hack may then find single or multiple heroes (players) and ambush them. A player using a map hack would also know if multiple players were coming to ambush him, giving him an opportunity to run away.
Bugging
Bugging is the most obvious form of cheating. Bugging allows a player to control another player on the opposing team. The former player will often make the controlled player commit suicide or drop valuable items. If a player is unable to shake the bug, she may be forced to leave the game to avoid harming her own team.
Spying
Spy programs are used to gain information about opposing teams. A spy program can hack into a private chat channel, give information about weapons, armor and levels of opposing players as well as alert the player if an enemy approaches. Spying can be used in multiple game maps in addition to "DotA."
Ban Lists
A ban list is a program that works to remove cheaters from future games. A player starting a game can load a ban list that allows him to see if players joining the game have been kicked out for cheating or have left a game before of after it started. The player can then boot the cheater from the game.