While such revenue numbers are tiny compared to PC-based searching, they represent a big change for companies, for a number of reasons:

1. It's more personal than any technology we've seen before.

Partly that's because people carry their cell phones with them in the same fashion as they do their wallets. That should mean the cell phone lets companies personalize their messages to customers d in new ways. Already, one of the main reasons companies use technology is to tailor their sales efforts to their customers. But personalization remains a challenge. Mike McCue remembers working at Netscape in the early 1990s and thinking, "We really have to figure out this personalization thing". Netscape's effort fell short, as have many other personalization efforts since then, because the Internet is not a personalized platform. But McCue, founder of Tellme, a voice-driven search engine.

2. It could be the biggest tech phenom ever.

Personalization is an obvious reason to find the cell phone search market attractive. There are about a billion other reasons to find cell phones intriguing. IDC says that's how many cell phones will likely be sold worldwide in 2008—versus probably just over 300 million PCs...

3. People will search differently on cell phones.

The difference between Internet search and mobile search looks to be substantial. For starters, almost by definition, people who use their cell phones to search are probably on the go or will be soon, based on their search results. The two main categories of mobile search right now are those who want to buy something immediately, and those who are looking for a place, says Greg Sterling, who runs the local mobile practice at Opus Research in San Francisco. (Read our Best BlackBerry Shortcuts.)

So it's location-driven. That penchant for action makes the cell phone search market a huge opportunity for business, but an opportunity that is also a huge challenge.

4. There is no Google for mobile search.

Not yet, anyway. Of course, Google itself may come to dominate mobile search in the way it does desktop search. But right now, search on the mobile phone is not the monolithic thing it is on the computer, where you primarily have Google and a few other search engines with lots of little niche technologies.

That's in part because there is not yet a well-developed market for mobile search. The results paradigm is probably different—it's even less useful to get a million results on a mobile phone than it is on a PC. As McCue notes, "All the search algorithms need to be reworked to give you three results max."

How to charge for advertising is also not clear—although if mobile phone searches do tie in more directly with sales, that will probably cost more than comparable advertising on the desktop.

That market may be different—more local and more specific than Internet search. "It's pretty hard to monetize a search for Justin Timberlake, or to do complementary or ad-based kinds of advertising," says Craig Hagopian, the executive vice president and CMO of V-Enable, which, like Tellme, is a voice-driven search engine. Also, phones have built-in GPS devices, so search engines have a pretty good idea that if you're searching for a store from your phone, you want the one nearest to you.

There is one form of mobile search that resembles today's computer-based Internet search: Wireless Access Protocol (WAP). About 5 percent of sites support WAP, which aims to bring the Web-browsing experience to mobile-phone screens. But it is certainly not the primary way people search on mobile phones.

5. Your business can't expect to give the same old search response.

Sterling notes that mobile search will yield things like product searches from stores as customers comparison shop. Customers may also use these searches to check for product availablity—the Nintendo Wii being an example of something that consumers might search for on the fly. Companies need to think about how to respond to these sorts of searches.

"That stuff is coming—the infrastructure that will support this is substantially already built," says Sterling.