A derogatory term for the InterNet, reflecting on the view that the InterNet and the WorldWideWeb are synonymous. The misspelling with an "a" came to be accepted as a self-ironic but also post-ironic reference reflecting on the amount of crap that fills the Web.
The original source of the term is not known, but it does appear in an old PSIS Internet banking advertisment. The old man, who's portrayed as non-Internet savvy, mentions that he can do his banking on this "IntarWeb Thing", and that his son in law (I think) should do the same (but he already does, as he's Internet savvy!).
IntarWeb BAD! -- James Hetfield