I read an article from BusinessInsider by Dan Frommer today around the top mobile advertising platforms.

We’ve been covering this sector over over a year and a half, years and in that time we have seen AdMob get bought by Google and Millennial rise to the top of the independent list. It’s a growing and changing market. One thing that isn’t always clear to the average tech news follower is the distinction between search and display mobile ads.

BusinessInsider writes:

…the U.S. mobile display ad market is still very fragmented, and no single company has more than 20% of the market, IDC says in a report.

Some highlights:

* The mobile display ad market was about $390 million in 2010, according to IDC. Google had 19% share, Apple had 18.8% share, and Millennial Media had 15.4% share.

* Apple’s share is particularly impressive because it only started iAds in the second half of the year.

* Google is crushing everyone in mobile search advertising, commanding 91.4% of the $487.3 million market, according to IDC. Yahoo had 2% of the market and Microsoft had 1.6% of the market, IDC estimates.

* Google’s combined presence in search and display make it by far the biggest player. But it has hardly dominated mobile display advertising, which is why it spend $750 million on AdMob in the first place.

* IDC expects the market to reach $1.9 billion in 2011, including search.

Again, the key is to break out display from search. For display ads on mobile, the market leaders (aka the big three) are: Google, Apple, and Millennial Media. For the remaining independent companies left as acquisition targets, the distance between Millennial Media and the other ‘independents’ is huge and growing.

Recently, via a 4Info blog post, Nielsen put out some numbers on mobile reach. Mobile is a hard market to size, but display is the main game on the device. From what I hear, Greystripe, Mojiva, inMobi, and other indie mobile ad players don’t participate in Nielsen, Usually this is because either they don’t have the traction or their internal systems are up to par.

As demand keep soaring for mobile inventory the ad side will shake out. Once the top guys align and the small indie players get rolled up the game will be more efficient.