Without question, Twitter is a great disrupter of the industry I've spent my career in. But how that translates into a business, especially with a need to draw advertisers, remains to be seen.

In the meantime, if you really want to know what can go wrong -- and you should always want to know that if you're an investor -- get a hold of as many analyst reports as you can. Then do what I do: Scroll to the very end. That's where they usually list the risks to their investment theses.

As I learned back in the glory days of the Internet bubble, when arguing the merits of an investment theory seemed foolhardy, those risks often proved to be prophetic. I have no idea which risk factor will be most important for Twitter, but the one that has grabbed my attention the most is also the most obvious. It constituted the last two to be listed among the risks at the tail end of Susquehanna analyst Brian Nowak's impressive 50-page report: "Low profitability and the continued need to spend to drive growth."

Yes, even Twitter eventually has to make money.

Of course, I said the same about Amazon and Netflix.

Too early to say where Twitter will fall in that mix.

(Originally published on Real Money)

-- Written by Herb Greenberg

Herb Greenberg, editor of Herb Greenberg's Reality Check, is a contributor to CNBC. He does not own shares, short or trade shares in an individual corporate security.

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