(FORTUNE Magazine) – In the case of a few domain names--those cryptic-looking addresses on the Internet--the owners are quite obvious: ibm.com and monsanto.com, for instance. With other names, the link to a proprietor is more tenuous, but with a little head scratching not so difficult to figure out: funds.com (Fidelity Investments) and liquidplumr.com (Clorox). Some names, though, you'd never guess in a million years. How about diarrhea.com and hotdogconstructionco.com? To whom do they belong?

The answer in a second, but first a word of explanation: To communicate on the Internet, each computer needs a home address. Among cybertypes, this ID is called the Uniform Resource Locator, or URL, which includes a name, a period, and a suffix denoting the kind of entity the computer belongs to ("com" is the suffix that stands for commercial). The company that registers domain names in the U.S., Internet Network Information Center, or InterNIC, accepts names on a first-come, first-served basis. Once a name is selected, it's gone for good. (The company recently decided to charge $50 per name per year.) To prevent rivals, pranksters, and bored teenagers from nabbing names, companies are frantically signing up corporate IDs and product lines. Fidelity recently nailed down about two dozen domain names, though the mutual fund giant was beaten to its actual namesake by tiny Fidelity National Los Gatos of San Jose.

So who is the owner of hotdogconstructionco.com? Kraft--something to do with its Oscar Meyer brand, no doubt. And the proud parent of diarrhea.com? None other than Procter & Gamble, which has registered some 90 names since August, including pimples.com, dandruff.com, and underarm.com. Says P&G spokesperson Elizabeth Moore: "We are providing ourselves with more than one avenue to reach consumers with helpful information. We make Sure, Secret, and Old Spice. Underarms are important to us."

--Ani Hadjian