[AaronBrown]

It's hard for me to construct a situation in which seeing one card would make you call or raise preflop when you otherwise would have folded. Seeing the card <u>would</u> make you fold some marginal hands you might otherwise play, for example if you would usually fold a pair of Queens or lower if you saw the player on your right a matching card. You might fold something Ax, if x is less than a Queen and calls with an Ace. Suited cards are less valuable if he has a match to the suit.

So a few times an hour you'll fold a marginal hand that might have cost you an average of small fraction of a BB. Similarly, you might pick up a little equity by knowing an out is gone for you or another player. Both of these effects together are probably on the order of 0.2 or 0.3 BB/hour.

The big advantage is when you and the player on your right are heads up in the pot. For example, if you see a heart in his hand and the board has three spades, you don't have to worry about a flush. Your top pair is far more powerful if you know he has at least one lower card, since he cannot then have a higher pair, and he's less likely to pick one up.

I think this is where the big advantage lies. This might be only one hand per hour, but it could earn you 3 BB or more.