I've heard of them, but what exactly do they do?

What is a Keylogger? Many people ask this question, But still, the answer is simple: it's a software program that causes every keystroke typed on the computer to be recorded. A keylogger is capable of recording everything the user types in, including emails, documents, login names, passwords, bank information, Internet URL's, chat conversations, etc. Keylogger software. If properly coded, is absolutely impossible to detect, unless you know exactly what you are looking for.

Hmm, What would you look for if you suspected one? (I don't suspect one, don't have any thing that would have it, I guess?)

http://www.fileheaven.com/Keylogger-Hunter/download/4165.htm

Can that prog be trusted? (Knows he willl sound stupid throughthese boards) no viruses, no spyware, no adware in it?

it is listed at http://www.spychecker.com/software/antispy.html for download, and that site can be used to lookup programs that are spyware/adware http://www.spychecker.com/ using their search for keylogger hunter it responds "nothing found"

The best keyloggers are those built into the actual kernel (not Windows, something to which the source code can obtained). The second best are those posing as device drivers or modules. Common on Windows. The third best are viruses (some would say trojans) which attach themselves to (or run as a child process even) of regular processes. These could also be built into the program (much more effective). The fourth best are hardware keyloggers (maybe an adaptor on your keyboard, or inside your keyboard). The least effective are seperate processes which dump to a file in memory or the hard drive. Relax, unless you have valuable (as in the-general-malicious-technical-person-would-care about-valuable) information, there is little incentive to go about the trouble of running a keylogger off your system. As an end user, your biggest threat is automated, malicious code. Granted a keylogger could be automated, but it's not common (or useful) in mass exploits.