The Internet is an overwhelmingly powerful source of information, but the technology for harnessing that information, for getting it filtered and delivered how and when we want it, is still in its infancy. If you don’t believe it, see what kind of useful information you get when you Google “What kind of harmonica should I get for my 10-year-old?”

Recently, though, a flock of new services have cropped up to deliver highly targeted answers by passing your queries on to a sea of strangers. Call it informational crowdsourcing.

Some are simple Web sites where you can post a question for all to see, then wait for random Web users to reply. That’s how Yahoo Answers and work. “What’s a good starter beer?” “Do you believe spanking is a good form of discipline?” “Is it cheating if I have chat-room sex?”

It’s a rather crude form of crowdsourcing. You have no control over who answers your questions, it’s all anonymous, and the answers may take days or weeks to arrive. Still, it’s fascinating to see what the world thinks.

If you want your answers faster, you can try a phone-based service like ChaCha. Call 800-2CHACHA and speak your question. In about a minute, a text message appears on your phone, usually with a clear, succinct answer.

“What’s that word that means when the sun, moon and earth are all in a straight line?” you might ask. And the text message comes in: “The straight-line configuration of 3 celestial bodies (as the sun, moon and earth during a solar or lunar eclipse) is a syzygy.”

Actual humans are on the other end—your personal army of research assistants. The members of this freelance army are paid 20 cents per answer, and they use Google and whatever other research tools they need. A one-line ad at the bottom of the text message pays for the whole thing.

But while ChaCha is a useful way to get hard facts (“What’s the last flight out of Chicago?”), it’s no good for soliciting informed opinions (“How should I punish my teenager?”). That’s where better targeting comes in. If you’ve managed to cultivate a circle of like-minded followers on Twitter, for example, you can get instantaneous answers to very technical or very specific questions. You don’t need a lot of followers to get fast, expert answers, as long as they are mostly in your industry or your field.

The ultimate instant-answer service, though, may be Aardvark. It combines the “who you know” aspects of Twitter with the real-time features of ChaCha and the mass-audience potential of Yahoo Answers and Answerbag. It’s good for getting both facts and opinion.

To use Aardvark, you sign up at, then you submit a question by e-mail, instant message, Twitter or ­iPhone app.

Behind the scenes, the service figures out who else in your extended social circle might be able to answer your question. It analyzes the profiles and interests of all your Facebook friends, and, if necessary, it expands the quest to their friends and even their friends. It pings only other Aardvark users and limits your question to a few people at a time, so there is no risk of spamming your entire contact list every time you want a hotel recommendation.

But that’s all invisible to you; all you know is that you get two or three expert, thoughtful responses within seconds. Aardvark is so efficient at delivering targeted information that the company attracted the attention of Google, which then bought it in February for $50 million. Fortunately, like all the services described here, it remains free.

In the end, it’s not technology that lends magic to these services and keeps them free—it’s psychology. People like to help out, to feel needed, to be asked for their opinions. In other words, Aardvark, Twitter and the other free-answer services may be ingenious new channels—but it’s human nature that makes them tick.