One-post wonder

A one-post wonder is a BBS user who registers to make exactly one post before disappearing. They typically think they have a new and devastating argument on a particular topic, but in reality their argument has almost always been refuted many times before. Presumably they're too ashamed to show themselves again after witnessing their "devastating" arguments get a righteous digital ass-kicking.

Examples

• Masonwheeler thought he could refute Mike Wong's article on the economics of Star Trek by pointing out that the Federation has replicators. He had nothing to say when several board members refuted his argument with ease.
• Ecofan thought he could pass himself off as a university physics professor and school everyone on global warming, but he failed to respond when challenged to prove his credentials.