leech n.
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.