I'm having some problems with users cheating my online game by using macros to automatically click certain spots on the screen in a certain order to automate various tasks without having to actually be playing the game. Are there any methods that can be used to block this kind of activity without having to plaster CAPTCHAs all over the site and ruin the experience for the honest users?
Edit: I forgot to mention, this is a website-based game, and not using flash.
As a programmer, I say to look for patterns in volume or timing of clicks. Simple bots will hit the exact same spots at very regular intervals and do it much faster than a human would be able to. This makes for fairly easily-identified patterns.
As a gamer and game designer, I say fix your game so it's not so mindless. Although there will always be a few power gamers who will do anything to get ahead, if more than a percent or so of your player base is resorting to this kind of thing, it's probably because you're making them repeat some mind-numbingly boring task a ridiculous number of times. Make playing your game fun and people will be more likely to actually play it instead of having bots stand in for them. Since making it fun typically involves building gameplay that is more varied than just "click these three spots over and over and over and over and...", then this will also naturally make the game more bot-resistant, since there won't be such a trivial pattern for the bot to repeat.
As Dave Sherohman said, make the game more fun.
If you can't do that, there are a few things you could do. It may be possible to change the UI in certain ways so that the bots can't just repeatedly click. If that isn't realistic, you could try to detect the bots by recognizing the patterns, and then alter the UI or give a CAPTCHA, sort of like how StackOverflow does it. This shouldn't annoy users too much, as they should almost never see it unless they are a bot.
Yes, the issue with your game is wrist - killing, mind - numbing, RSI - inducing "non - content".
You can fix the issues easily by making the game fun instead of a terrible grind.
No one should be forced to click the same button over and over again like a monkey to get ahead in a game - and I actually APPLAUDE everyone who fixed this bad gameplay issue by using his brains well enough to use a bot.
Actually, programming the bot is more fun than stupid clicking I guess and causes much less RSI.