The answer to that question is "LOTS!" You may have heard about the recent Korean and Chinese online poker-bot scandals, all of which have been significantly profitable, but this is just the tip of the "botberg!" Poker bots with artificial intelligence and anti-detection programming built-in are already good enough to be profitable in fifty to sixty percent of middle-limit and high-limit games, as well as tournaments. In the lower-limit games they are already cleaning up.
This situation will only get better for the botters. I predict that within 5 years sophisticated and VERY intelligent poker bots will dominate the online poker scene and consistently beat online poker's best "botless" players. I also think that within 7 years the majority of ALL online poker players will be using poker bots, for if they don't they will be at a real disadvantage.
My take on my take: Wise up now and get your bot!