[BluffTHIS!]

In that post I was talking about the possibility of collusion because 4 people out of 9 were from the same city, although I noted that I had never seen anything funny from them as I have on a couple occasions from others.

Also I mentioned in the course of the post and my replies the various types of collusion, but will now attempt to outline those types. If I have missed something, someone please elaborate.

I. Hard Collusion (more obvious and overt)

A. Best Hand Play - two players, one of who has the best hand, raise and reraise to trap a 3rd player for more bets when that player holds a good but worse hand. Usually what happens is that the colluder without a hand will fold on the river so that his hand is not shown and it is not seen that he had little if any part of the board. However, when that 2nd colluder picks up a backdoor hand and makes it on the river, you are left there saying WTF.

B. Making Protection Bets & Raises - this is especially applicable to pot limit. Let's say you are in the middle of two colluders with a good but not great drawing hand. That is you are willing to call a pot size bet and take 1 card off, but would not call a raise. So the 1st colluder makes a bet, sometimes only like 1/2 the pot, you call, and now the 3rd player who holds the temporary nuts that is vulnerable to an drawout, now is able to raise and present you with a much larger bet to call than if the action had gone check/check/bet. Thus players who collude like this will be seen to play more pots together.

II. Soft Collusion (more subtle and mostly impossible to prove)

A. Sharing Card Knowledge - sharing card knowledge in games with more hidden hole cards is a powerful form of collusion. Two colluders doing this can know when there drawing hand outs are lessened and thus not pay off your sets when they have draws they otherwise would play, and when a 3rd player is unlikely to have the hand represented, thus allowing some miraculous calls to snap off bluffs. Players who play like this will be seen to play few pots together, although by playing some together but passively, they by the combined made strength and drawing strength of their hands can have an equity advantage overall over a 3rd player whose hand would be a favorite over either one headsup.

B. Playing From The Same Bankroll - as I said in the other thread, this is the softest form of collusion. Even though the players may never make any overt moves to suck in or raise out another player, and even if they never signal to each other cards held, they are placing you in a position of having to beat a combined bankroll in which they will often have an effective freeroll to suckout with weaker drawing hands if they are also aggressive in stealing pots, just like the "thinking LAGs" I talk about in my LAG thread.

Again, and I first saw Ray Zee point this out a couple years or so ago here, in games with more concealed cards like omaha, stud and lowball, colluders are able to use such card knowledge much more effectively than in HE. So the higher levels you play in these types of games, the more it is worth it to a cheater to try to collude online. This doesn't stop me from playing, but it does cause me to be more cautious. And I have always in both live and online play followed the advice of Mike Caro and others, to simply leave a table any time you even think there is a possibility of cheating going on. Of course online it is limited to collusion, and you don't have to worry about mechanics and marked cards (which is why shuffle masters are wonderful in live games now).