'Bots' are illegal programs, 'taught' to play a certain way on specific variations of cards.
Most of these programs are easy to beat long-term, especially in low stakes cash games. They are not too tough to spot but you need to observe a 'player' for quite some time to notice the patterns.
They can be profitable in the lower stakes, but are obviously wide open to traps and counter-plays in the higher stakes.
There was a HUGE scam on Full Tilt not long ago in the Super Turbo games where a player was running a couple of these programs and making a killing. Obviously even these bots are succeptible to bad beats etc, but by playing only premium cards and 'learning' opponents likely moves, they win in the long run, especially in these short-stack games.
Imagine a 100% rock of a player, but aggressive and impossible to
bluff off a premium hand, not letting emotions into their decision making process and with flawless pot
odds calculations, also with comprehensive notes on every person at the table after a couple of games. Got it? Scary huh? Thats a bot!