I grew up in the mountains outside Lake Tahoe. A lot of the hilly roads have warning signs that say, "Rockslide Hazard Area."

My mom would always joke when we passed these signs: "What am I supposed to do with that information?" she'd say. "Drive faster? Drive slower? Turn around? Prepare my will?"

She had a good point. Maybe the sign is telling you to pay attention to the road, but shouldn't drivers always be doing that? Signs like these may do more harm than good, distracting drivers without giving them any actionable instructions.

I see the same complaint about a lot of investment articles. If an article doesn't tell you exactly what to do, what good is it?

Readers often want actionable information. Here, buy this stock, sell that one. Editors often want the same: specific, actionable advice readers can follow.

Some writers are good at this. It works especially well when discussing big-picture investing traits that should apply to everyone, like the importance of patience or the impact of fees.

But most of the time I'd say it doesn't work. There is no way an investment writer can give actionable advice to every reader because the writer doesn't know who his readers are. I don't know you. (Yes, you.) I don't know how much money you have. I don't know what your goals are, whether you need to put your kids through college, how secure your job is, how much market volatility you can stomach, what other assets you own, or how long you might live. So how could I possibly say, "Here's what you should do with your money?"

I can't. And no writer should. What's good advice for one person could be disastrous to another. There's a comparison here between financial advice and medical advice: A doctor can write an article saying something like, "You should eat a healthy diet and get some exercise." That's good advice, appropriate for almost anyone who reads it. But if a doctor wrote an article that said, "You should take 300 milligrams of Plavix each day," readers would say, "Whoa, wait. You don't know anything about my health history. I'm not your patient. How can you possibly recommend that?"

Most people instantly see the problem with a doctor offering blanket medical advice. But the same logic is often lost in the investment world. Smart people hear a guy on TV say "It's time to sell stocks," and they go home and sell stocks -- unmoved by the reality that the guy on TV knows nothing about you.  

So, here's the question: Are investment articles worthless? Or even dangerous?

If you take them all at face value, reading every bit of advice as a literal how-to guide for your own unique situation, then yes. Unequivocally, yes. So, please: Don't do that.

Investing media gets really fun -- and useful -- when you realize that it's not necessarily about specific advice you should take, but bits of information that help you solve your own personal puzzle. Every consumer of financial news has an obligation to know about themselves what the writer can't: Your own risk tolerance, age, job security, time horizon, and level of expertise, to name a few. You have to know these yourself so you can understand what kind of financial media is relevant to your needs, and what isn't.

Here's how Josh Brown, The Reformed Broker blogger and one of the smartest guys I know, put it last year:

Let me tell you something interesting about financial media. Of all the verticals across different types of news, financial media is the only one where there's supposed to be some sort of responsibility that comes along with it. When you think about fashion, art, sports, Hollywood gossip -- huge categories of news that dwarf financial news -- there is no responsibility. People don't watch ESPN and then think they're supposed to go out and play tackle football with 300-pound guys. But when they watch financial or business news, they then take the next step and say, "Well I'm supposed to act on this now. I'm supposed to do something about this."

Part of that is the fault of the media. The word "actionable" gets thrown around a lot. Actionable for who? Oh I don't know, it's just actionable. But a lot of the responsibility is on the public. And I think what most people do incorrectly is they focus on the news of the day, the stocks that are moving on a given day, whatever is driving the markets now, but they've got no background whatsoever about how to invest.

The flip side of this is that sometimes you'll read an article and want to scream, "This person is so wrong!" And maybe they are. But maybe they just have different goals than you do. Or a different outlook on life. Different priorities. Processing that information in a way that doesn't tempt you to go out and make a change to your portfolio can still be really helpful. It gives you new perspective on investing, and can teach you what not to do.

And watch out for the rockslides. 

Contact Morgan Housel at mhousel@fool.com. The Motley Fool has a disclosure policy.