When I say "the whole world," I'm only slightly exaggerating. Google indexes every tweet, so just about anybody surfing the Web should theoretically be able to sniff you out.

Let's assume you'd like to narrow your focus a bit. Start by checking your email address book. If you use Gmail, Yahoo, AOL, Hotmail or MSN, Twitter can trawl through your contact list automatically.

If not, you might want to hit up your teenage niece or nephew and have them enter your existing customers' emails by hand. Yeah, it stinks. But as of now, those appear to be the options for reaching your current customers via Twitter. Alternately, you can just send your address on Twitter (usually in the form of Twitter.com/YourUserNameHere) out with your regular correspondence and let them track you down.

For example, my Twitter feed is http://twitter.com/jsosa1234, Computing Unplugged's is http://twitter.com/computingunplug (because there's a limit to the letters you can use in a name), and our esteemed editor's is http://www.twitter.com/davidgewirtz.

To find new prospective customers on Twitter, you'll want to use the search feature. This lets you find people on Twitter based on what they're chatting about. Particularly savvy tweeple mark their tweets with keywords or "hashtags", which are a boon if you're looking for people talking about the IT field and not just people who use the word "it" in their tweets.

To search by hashtag, just precede the keyword with a #, as in #IT, #cisco, #film, #healthcare or #beer. There are many more advanced search functions, including a slick one that lets you narrow down results based on where tweeple reside.

Let's say you want to find everyone who's talking about wine within a 70-mile radius of Minneapolis. Your search query would look like this -- near:Minneapolis within:70mi #wine -- and would yield a list of geeky Twin Cities wine connoisseurs.

To use more advanced search techniques, check out the glossary of advanced search operators or just use the advanced search form.

When you find someone you want to share your message with, click on either their user name or photo. This will bring up their profile page. Click on the Follow button below their thumbnail picture and that user will get a notice saying you're following their stream of tweets. If they check you out and like what they see, they'll reciprocate.

Keep your audience
Now that you've found all these new potential customers, you'll want to make a good first impression.

If you're the kind of businessperson who has a strong spamming instinct, you'll want to check that instinct at the door. Spamming is against Twitter's rules, is extremely easy to block, and is a good way to generate ill will against yourself and your brand.

"Content is king" should be your mantra. And the best way to build a loyal following is to offer added value. For instance, instead of bombarding people with "Eat at Joe's", take a tip from the good people at Victor's 1959 Cafe and say, "Happy hour at victor's 1959 cafe right now and till 6:30pm. $3 beer / $4 wine / $4 tropical mimosas."