Just as you can't be sure of the age and gender of the person you're IMing in a chat room, you can't be sure that your opponent in an online poker game is human.
Poker playing bots are getting better, and despite online casinos' efforts to detect and ban them, they're here to stay.
Ian Ayres, an economist and lawyer at Yale, write about the rise of the poker bots on the NY Time's Freakonomics blog:
In the very near future, online poker may become a suckers' game that humans won't have a chance to win. Bots are quite scale-able and it will be virtually impossible to prohibit computer or computer-assisted online playing.
Poker sites are trying to assure customers that they will kick bots off their site and seize their assets. But unlike the statistical trail left by crude poker cheats at Absolute Poker, it is possible for bots to randomize their strategies and even hire individual humans to run them.
Ultimately the Albertus Polaris program and its offspring could be more effective than any Justice Department indictment in crippling the growth of online gambling. Indeed, our government might even think about subsidizing the development and use of these bots.