leech

n. (Also leecher.) Among BBS types, crackers and {warez d00dz}, one who consumes knowledge without generating new software, cracks, or techniques. BBS culture specifically defines a leech as someone who downloads files with few or no uploads in return, and who does not contribute to the message section. Cracker culture extends this definition to someone (a {lamer}, usually) who constantly presses informed sources for information and/or assistance, but has nothing to contribute. See {troughie}.
v. [common, Toronto area] v. To download a file across any kind of internet link. "Hop on IRC later so I can leech some MP3s from you." Used to describe activities ranging from FTP, to IRC DCC-send, to ICQ file requests, to Napster searches (but never to downloading email with file attachments; the implication is that the download is the result of a browse or search of some sort of file server). Seems to be a holdover from the early 1990s when Toronto had a very active BBS and warez scene. Synonymous with {snarf} (sense 2), and contrast {snarf} (sense 4).