Rumors abound that Apple is thinking about further severing its ties with its new competitor in the smartphone market, bouncing Google and giving Bing premium search placement on its mobile Safari browser. If the rumors are true and Bing becomes the default search engine, there could be a reversal of mobile-search fortunes.

Consider the implications behind the statistics. According to Chitika Research, Google is pulling healthy numbers from iPhone users. Specifically, Google search makes up just more than half of all Internet traffic on the iPhone.

That number is even more significant when placed in this context: It outnumbers the entire genre of non-search traffic. Non-search traffic includes typing a URL directly into the browser, navigating to bookmarks, and clicking links from any non-search site.

Google's iPhone Dominance

If those numbers aren't enough to get the mobile industry's attention, consider how Google's iPhone stats compare with the general Internet. According to Chitika, non-search traffic makes up 65 percent of all web usage for non-iPhone users (mostly people surfing the Internet on PCs). And Google search traffic makes up about 31 percent of overall Internet traffic. Chitika points out that this is 20 points lower than Google's iPhone stats, yet it is still considered the dominant source of search traffic.

In all, Google sees 1.46 million impressions on the iPhone each month. By contrast, Yahoo sees nearly 36,000 impressions, and Bing gets a mere 2,387 impressions. Bing is climbing up the mobile-search ranks, though, already surpassing Ask with its 2,348 impressions and AOL with 401 impressions. The iPhone also dominates total smartphone traffic, with about 28 percent. Android is closing in on Apple, however, with 27 percent, while Research in Motion holds only 10 percent.

"How can Google be so dominant on the iPhone?" Chitika researchers asked. "Simply put, the way people browse through the iPhone's Safari means that the quickest, easiest way to browse is by using the default search box at the top of the browser. Typing a full URL is unwieldy to many with the virtual keyboard, and browsing sessions are likely shorter than they would be on a laptop or desktop, leading to less opportunities to click from site to site."

Will Apple Bring on Bing?

Chitika researchers pointed out that if Google loses its status as the iPhone's default search to Bing, it could mark a massive shift in mobile web superiority. Although Google's Android is growing its market share at a high rate, the iPhone still makes up 54 percent of the increasingly valuable mobile web market. Google has recently shown that mobile advertising is a very high priority, given its acquisition of AdMob in November, so a swing of more than a quarter of the smartphone market from Google to Bing would be a huge blow to the company's plans, Chitika concluded.

A Bing placement on the iPhone's deck would be a huge deal, said Greg Sterling, principal analyst at Sterling Market Intelligence, because it would expose millions of users to Bing -- millions who could start using Bing on a regular basis.

"The risk for Apple is that they could run into the problem Verizon had when they substituted Bing for Google, which annoyed some of the users. I think Apple is probably more thoughtful than Verizon. If they were to do something like that, they would do it in a way that would not be so disorienting to end users," Sterling said. "But I do not think Apple is going to do a default deal with Microsoft. I could be wrong. I do think they will make Bing an option, which is what they should do."