A Hacker is an individual who uses illicit means to gain access to computer files, most often over an internet connection. Hackers "hack" (break into computer networks) for notoriety, peer recognition, and profit. Targets can include banking websites, online sales sites, and individuals. Social networking websites and other sites which call for user participation are particularly vulnerable to hackers and hacking because of the limited knowledge users have and the high level of downloading and uploading which takes place on these sites. Hacking is illegal and can carry strong penalties.