Pretty Neat

We've played some cards over the years, including electronically. We found this very interesting:

Here's a fascinating account of a "side-band" attack on online Blackjack. At a certain point in the gameplay, the software dealer appeared to need substantially more calculations if there was a ten in the dealer's hole than if there wasn't. Players who timed the pause could therefore get a partial peek at the dealer's cards and so gain an edge over the house.

In Poker, this is called a "tell" -- the propensity of a player with junk to mop his brow, or of a player to unconsciously tap his foot when he's bluffing. Computers are generally considered not to have tells, because they're not sentient and hence not prone to subconscious fidgeting, but computer tells do arise in those situations where they are doing something computationally intensive.

Link.