The vast majority of the "hacker" underground is made up of people who have only been using computers for a few years and who really know comparatively little about them. These are people, usually kids, who are attracted by the seemingly magical powers that hacking gives them. Since they know so little about computers, they don't really known how to hack themselves but instead follow recipes or "scripts" developed by real hackers. Most of these scripts are easy-to-use programs whereby the "script-kiddy" simply enters the IP address of the victim.
One of the distinguishing features of script-kiddies is that they must have a lot of patience. Because security holes are quickly found and repaired, most systems will resist most attacks. Therefore, if the script-kiddy is targeting a single system, they have to find a lot of scripts to try against the system before they find one that works. More commonly, the script-kiddies downloads one of the most recently developed scripts and proceeds to run it against targets all throughout the Internet until they find someone who is vulnerable to that specific script.
Because of the ease-of-use of these programs, there are hundreds of thousands (if not millions) of script-kiddies on the Internet. This has generated a certain "background-radiation" on the Internet. Any machine connected directly to the Internet with a high-speed connection will likely see a fair number of attacks against their system from these script-kiddies.
