"That means that if the market is anywhere cl...

"That means that if the market is anywhere close to being efficient, "
It's not. Everyone's who's actually in the market knows this. Most of the participants don't even read the annual reports of the companies they "invest" in, for God's sake.

"But OK fine, suppose the market is not efficient. Suppose there are some smart people who can interpret the public news really well, and some suckers who take home the wrong message."
Yes. This is true. Benjamin Graham wrote an entire book on how to read financial statements (public information) in order to get the right message rather than the "sucker's message" which the corporate boards were trying to peddle.

"Because there's another problem here. If the writers of Zero Hedge really knew some information that could allow them to beat the market, why in God's name would they tell it to you? If they had half a brain, they'd just keep the info to themselves, trade on it, and make a profit! "

Often true. But it depends.
* Sometimes (as in the case of Naked Capitalism) the writer has an agenda other than making money. These can be very useful. The old Wall Street Journal news pages, before it got trashed by Murdoch, were an example: the reporters' goals were to break news and become famous, so you could trust their reporting of the Enron crimes, etc.
* Sometimes (as in the case of annual reports) the writer is being forced to publish by outside forces, but really would prefer not to publish at all. These can be quite useful but require *decoding* because they're deliberately misleading.

"after they had made their profit, they'd release the news to the public (and collect ad revenue), but by then the news would be worthless."
This is a very cogent argument; after the Enron news broke, Enron dropped massively. However, it didn't go to zero until some time later, so you still got some value out of reading the news when it first broke rather than the week after. So there is also the fact that a startling number of people take a very long time to accede to reality; it is possible to identify a situation when *many* people have identified it but many are still contrarian.

None of this negates your general point -- which is, basically, that someone selling a "hot stock tip" is *never* useful to listen to. But I have catalogued for you the specific situations in which reading financial news can actually help you trade better. (Remember, never take their *advice*, read their information and then analyze it yourself.)

I trade less than five times a year. The most useful information I've ever gotten from online sources was the hint in 2007 that maybe the financial institutions didn't know what the hell they were doing, which caused me to drill down into the annual reports of all the financial institutions I owned stock in, decide that several didn't know what they were doing, and sell them all.

But then I realize I'm looking for different things than the average male investor. I'm scanning the news for evidence of disaster in investments I already own, which is quite the opposite of optimism bias.

A lot of the writers at Zero Hedge are absolute bullshit artists, but a few of them are digging up genuinely useful data which is worth reading. I suspect they use it *because* of the anonymity; they are probably insiders who are trying to reveal corruption without getting fired. If they weren't in that position they'd just publish under their names at Naked Capitalism or The Big Picture or whatever. The insider leaks there are by far the most useful thing at the site, and if you're watching for signs of collapse of certain companies, they're actually worth paying attention to (though you need to do your own due diligence to see whether they're plausible or just libelous).