Glag is a slang term for the collaborative act of flagging Craigslist for-sale postings that are obviously spam, scams, shady deals, or otherwise exploitative. Craigslist is a central network of online communities featuring free online classified advertisements – with jobs internships housing personals, erotic The Craigslist flagging system allows anonymous, vigilant users to "complain" about a given posting and if enough flags are received, Craigslist will remove the posting. Glagging typically employs the "prohibited" and "spam/overpost" flags, with the ultimate goal of thwarting scammers and protecting legitimate users. A confidence trick or confidence game (also known as a bunko, con, flim flam, gaffle, grift, scam, scheme
Though disputed, the word is thought to derive from "gang flag", owing to the collaborative nature of glagging. It has also been called "giga-flag" which has a scale quality to it.