Things are not as they seem in online advertising, or at least not as they've been characterized in political and financial circles. While Google has been receiving scrutiny of late, AOL's strategy to take the lead while no one's looking may be working.

While Google continues to be the Internet's principal search engine, now with a 67% share of US searches according to Hitwise numbers released last week, the popular presumption is that its reach in search translates directly to its reach in advertising. Microsoft was counting on that association in its campaign against the Google + DoubleClick merger -- a campaign which, of course, completely failed.

But while some have been hearing the AOL name crop up in popular discussions again as the possible white knight in a rescue of Yahoo, the firm has actually been mounting a clandestine charge in the advertising department that only now is being discovered. Since January, it has coalesced its Advertising.com platform along with some of its recent acquisitions, including textual ad platform Quigo, mobile ad platform Third Screen Media, and behavioral ad platform Tacoda. Now, all of those are doing business as Platform-A (and, to help symbolize the bond, AOL has been more prominently displaying the combined firm's hyphen, which we had previously been omitting).

And since audience measurement firm comScore has been tracking the new Platform-A, its reach -- the number of pairs of eyeballs it's capable of attracting -- has risen. In the latest measurements, Platform-A experienced nearly 2.5% month-to-month growth in US audience reach, attracting 170.5 million Web users, or about 91% of the total audience.

By comparison, Yahoo's advertising network runs second with an 85.3% reach and about 160.3 million viewers, and Google's celebrated network -- what has been characterized as the lynchpin in a prospective monopoly -- is third on comScore's list, with an 80.9% reach and 152 million viewers.

Reach, obviously, is not analogous to market share; different networks can reach many of the same viewers, but some reach more than others. Just last January, comScore estimated that Advertising.com -- the principal unit in what is now Platform-A -- reached only 163.8 million viewers or an 89% share of the US audience at the time -- not much more than where Yahoo sits now. And prior to the transition, Advertising.com reached 156.6 million viewers last November, an 86.6% share and just about 1.3 million viewers above one-time market leader Yahoo.

When the acquired components were tacked onto Platform-A's share at the beginning of the year, there was considerable overlap, so the net gain at first looked like just under 3 million US viewers. But now, it appears the coalition is paying off, as it puts some serious distance between itself and the competition.

A hypothetical combination between Yahoo's and AOL's operations to stave off a hostile Microsoft takeover would probably result in only one of those platforms surviving, as BetaNews speculated last week. With Platform-A's demonstrated ability to absorb other operating units and make that absorption pay off, it's looking more and more like AOL could end up the advertising division of a theoretically combined Yahoo, should that merger ever come to fruition.

Microsoft's Windows Live ad platform was actually driven off comScore's #15 slot by Burst Media, the targeted network group run by Jarvis Coffin, who is no stranger to BetaNews.