Yahoo! (Nasdaq: YHOO) ought to be giving Apple (Nasdaq: AAPL) an attaboy. The computer maker is indirectly helping Yahoo! in its quest to steal mobile-advertising revenue away from Google (Nasdaq: GOOG).

For every Android-based phone that's sold, Google stands to benefit by reaping more mobile-advertising revenue. Google has done a phenomenal job over the years enticing handset makers such as Motorola Mobility (NYSE: MMI), Samsung, and HTC to use its free Android mobile operating system on their smartphones and tablet computers -- so much so that Google's slice of the $2.1billion mobile-advertising market is expected to soar to 23.8% this year for its mobile display advertising, compared with 18.8% last year. And that's not good for Yahoo!, which has its efforts squarely focused on boosting its display-advertising sales -- both mobile and online.                                    

But recently, the U.S. International Trade Commission sided with Apple on one of its four patent-infringement claims it filed against HTC. Under the commission's ruling, beginning April 19, HTC will be banned from importing smartphones that allow the capability to recognize telephone numbers, according to a Bloomberg report. That potentially reduces the number of HTC Android-based phones coming into the U.S. market until HTC gets a workaround in place.

For Yahoo!, that's obviously good news on the mobile-advertising front.

British Telecom weighs in
And Apple isn't the only tech titan accusing Google of violating some of its patents with the features it loads into Android. Earlier this month, British Telecom weighed in with its own patent-infringement lawsuit.

The European carrier alleges that Android's location-based services, personalization tied to content and services, navigation, and guide information constitute thievery of its technology. It's seeking not only financial relief but also an injunction.

Yahoo! investors should be interested in the injunction or any efforts that would slow down the distribution of Android-based mobile advertising -- er, mobile software.

Carrier Verizon has long been a staunch supporter of Android, and it would be surprising to see it take a similar tack as British Telecom, but now that it has the iPhone, it may look deep into its patent portfolio for any potential violations.

Oracle takes a shot
Oracle (Nasdaq: ORCL) is another tech behemoth that has filed a patent-infringement lawsuit against Google over its Android software. Last year, the enterprise-software giant alleged that Android's Application Programmer Interface (API) took its cues from Oracle's Java API packages.

Although Oracle wants upwards of $1.4 billion for the alleged infringement, it's smart to realize there is more money in gleaning a bit of Google's mobile-advertising revenues. It's also asking for 15% of the mobile-advertising revenues derived from the Android platform.

The parties are trying to hash out a settlement, and the trial has been postponed from its October start until the new year, according to an IT World report.

Yahoo! investors should keep a keen eye on this fight. APIs are a critical part of the software makeup, and should the court ultimately find Google needs a Java license and Oracle wants to play hardball, Google's mobile-advertising revenues could take a hit if it has to hand over a large chunk of its advertising to Oracle.

Although that won't put money into Yahoo!'s pocket, it may help to narrow the comparison gap between the two Internet companies.

Yahoo! should marry Microsoft
Microsoft (Nasdaq: MSFT), a significant Yahoo! partner on search technology and its advertising efforts, is fooling around with Google's Android, and it's not even doing it behind Yahoo!'s back. Yahoo! should have tied the knot with Microsoft years ago -- then it could have benefited from the software giant's philandering ways.

With Microsoft collecting royalties from members of Google's Android ecosystem, it's lining its deep pockets quite nicely. As noted in one Motley Fool report, Microsoft has more than half of all Android-based devices having to pay a licensing royalty.

Too bad Microsoft doesn't add a clause in those agreements that Yahoo! gets a cut of all mobile-advertising revenue that some of these Android ecosystem players generate.

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