Crucial, complicated questions. But what about when somebody who claims not to be a journalist writes some obvious nonsense — say, about a company — and a whole lot of people, including people on Wall Street, decide to believe it? In such a case, the question of who is and is not a journalist seems beside the point. People read it, they believe it, and sometimes, they act on it.

Case in point: late Wednesday, tech gadfly and blogger Robert Scoble wrote on his Google Plus profile: “I just heard an interesting rumor. Supposedly Google (BBY) is renting 6,000 square feet inside every Best Buy (BBY) next year. Why? My source says it’s to sell Google Glass.”

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Despite the ludicrous notion that Google Glass displays could take up 6,000 square feet (which would amount to nearly a third of the smaller stores, and more than 10% of the biggest), the post was taken seriously. The Pioneer Press, a hometown paper of the Minnesota-based Best Buy, reported that the rumor boosted the retailer’s shares by 4% on Thursday. The paper offered zero evidence that the stock spike was related to the rumor, but given that Scoble has a pretty big audience (nearly 350,000 Twitter followers, e.g.), it seems a safe bet that he was at least partly responsible for the uptick.

But Scoble, though he weighs in constantly on all manner of tech stories, also insists that he’s not a journalist. That makes it possible for him to have it both ways. He can write something for his huge audience, without ever taking any responsibility for it. “Now, this is a rumor,” he wrote on Google Plus. “If I was a journalist working for, say, Techcrunch, I’d call around and see if I can verify this rumor. But I would rather let this hang out here and see if someone like Kara Swisher knows anything.”

On Twitter, Kara Swisher, who runs the Wall Street Journal‘s All Things D blog and who openly admits that she’s a journalist, wrote to Scoble: “No idea! Aren’t you the expert?”

It’s quite possible, of course, that Best Buy and Google are in some kind of talks. Everybody is always in some kind of talks with everybody else. Maybe they’re even in some kind of talks for a Google Glass store-within-a-store (that would comport with Best Buy’s current strategy, which investors seem to love). But when a rumor like this is accompanied by a ridiculous assertion — 6,000 square feet — the whole thing should probably be taken with a couple of cases of salt. The fact that it wasn’t — by stock traders and by online commenters — confirms two things: in the short term, Wall Street is always insane; and many online commenters will believe anything.

The Pioneer Press, for the record, contacted Best Buy, which said it had nothing to announce.