What’s the No. 1 best-kept secret of Twitter? That it’s a client prospecting tool and market intelligence tool. All rolled into one.

Using just a few easy methods (detailed below), you can be typing in key words and searching Twitter for mentions of competitors in your geographic area — sometimes down to within 1 mile of you. But it goes beyond that. Want to read all the tweets sent to your biggest competitor from anyone? You can. Want to read all the conversations from your competitor to customers? You can.

How can this be possible? Because Twitter is a public medium. What you say on Twitter (except through direct message) … Does NOT stay on Twitter. It’s indexed by Google. All of it.

The best way for businesses to use this built-in intelligence tool is to:

• Monitor your competition
• Monitor mentions of a service or product
• Find customers looking for a service or product
• Monitor attitudes about a competitor – or service or product

These are all ways to gather market intelligence and to prospect for clients.

The tools are so easy all they take is the time to type in key words and click a couple buttons. Each search should take you 10 seconds or less.

Here’s how:

Method 1. Use Search.Twitter.com (which is NOT the same as search bar on Twitter)

Go to Search.Twitter.com. This is owned by Twitter so don’t start crying and freak out thinking this is some kind of robo tool used by “get rich on Twitter” twerps.

Use it to gather info on competitors:

To find any tweet TO any twitter account just type in “to:NAME” where of course “NAME” is the name on the Twitter account. Don’t use the @ symbol, just the name of the Twitter account. What you’ll see is everyone on Twitter who has sent a Tweet to that account … and the entire conversation in replies! Below each search result you’ll see “Show conversation.”

You can use the same method to read all the tweets FROM any account and their conversations. Just type in “from:NAME” instead of “to:NAME.”

Use it to find people looking for services/products in your area

Click the “Advanced” tab next to the search bar, and a whole new world opens up. You can search by words, people, PLACES, dates — even “attitudes” (positive or negative tweets).

Under the “Places” section you’ll see “Near this Place” field where you type in your town. Then below that you can click the radius of the search in 1, 5, 10, 15, 25 miles (up to 1,000). How you use it is up to you, but the ability to search by your local area should give you a leg up on your client prospecting work.

Note also that all search results have an RSS feed icon — so you can feed these in real-time to your RSS reader. How cool is that?

Method 2: Use search-generated tabs on HootSuite/TweetDeck/Seesmic

If you use a monitoring tool like HootSuite, TweetDeck or Seesmic, then hooray – you’re probably familiar with the client prospecting work mentioned above. If not, jump in – these tools make subject/name searching very easy. I know Hootsuite the best, so suffice to say I’ll use that as my frame of reference.

Create streams for key word searches

In HootSuite (and the others) you have a search bar, which then creates results that you can “Add to stream” and monitor any time you wish. Of course, to make your search local just type in your town and the key words you’re looking for (or the town and your competitors’ names).

Use the local search function

But an even better way to ensure a local result is to click on the circular icon within the HootSuite search bar itself. This ensures you get a local result (which of course you can then “add to stream” and monitor in real time).

I must report however, that there’s no customization of geographic area on HootSuite’s local search (like Search.Twitter’s ability to search by increments of 5 miles). At least not on their “free” version (they now have several pay account versions) Also, it appeared a bit “sticky” to me — I sometimes waited some time for a search result to pop up.

So why use a search result tab in HootSuite/TweetDeck/Seesmic? Because these Twitter monitoring tools make viewing multiple streams easy. You don’t have to check your RSS feed if you always have one of these apps open all the time. You just scan over and see what’s new on that tab.

So start searching! For some businesses, the info you dig up may lead to new clients or product or services.