Mobile Ad Networks
Mobile Ad Networks are third party platforms which provide mobile app developers an opportunity to generate revenue for their free apps through advertising and user data brokering. App developers typically use multiple Ad Network platforms within a single app. Fill Rate, eCPM, User Experience, Technology Platforms and Payment Options are some of the major factors that differentiate mobile ad networks.
Mobile Ad networks were created to help App developers who were trying to collect inventory from a seemingly infinite number of websites and publishers. App developers and marketers didn’t have the time or resources to cherry pick ad impressions from each website, so ad networks were created to present a large collection of inventory so app developers could buy impressions quicker, easier, and cheaper. Not all Ad networks are created equal. Some choose to focus on reach and quantity while others boast the quality of the spots they sell. Ad networks aggregate inventory from many publishers and then mark it up and sell it to profit. 
At a high level, ad networks exist to help marketers achieve reach and scale in a fragmented online display ad marketplace. Ad networks help by bringing together inventory, and more to the point, audiences, to enable marketers to buy online ad impressions faster, more efficiently and cheaply. There are many different types of ad networks. Some focus on reach and price and don't provide much insight on who or where. Other, more premium networks -- including publisher-specific networks -- are all about guaranteeing audience demographics and quality. 
A Mobile Ad Exchanges are different from a Mobile Ad Networks. Ad Exchange could potentially be compared to a stock exchange. While it’s not exactly similar, it does serve as a platform to increase the efficiency of the online ad market by making ad impressions readily available so app developers can search for and choose the ads they want at the price that’s right for them. Like demand-side platforms, ad exchanges seek to add stabilization and transparency to the ad network systems, which caught criticism in the past for being monetized to serve interests of sellers. At the moment, it isn’t able to function like an exact exchange because there is not a natural balance of supply and demand in the online ad marketplace. 
Mobile Ad Exchange vs. Mobile Ad Network
If an ad network is like a closed group of privately traded ads, an ad exchange could be compared to an open network where buyers can see all the options available. However, ad networks often come to ad exchanges to buy bulk ad impressions to re-sell, which does create a level of inequality in the ad exchange market. Overall, an ad exchange can be seen as offering variety, while ad networks offer specialized groups of ads that cater to a marketer’s needs. Ad networks may take the trouble out of searching, but they also display inaccurate costs to include profit for the network providers.
History of Mobile Ad Networks
- In 1996, DoubleClick was founded as one of the earliest online ad exchanges
- In 2006, AdMob the first Mobile Ad Network was founded
- In 2006, Millennial Media, the second Mobile Ad Network was founded
- In 2009, Google bought AdMob for $750 million
- In 2010, Apple released its Mobile advertising platform, iAd
- In 2012, Facebook launched its Mobile advertising network
The fill rate is calculated by dividing the number of ads delivered by the number of ads requested by an app. Zero fill rate means an app may display an empty space in the area of an advertisement. Most popular ad networks have a fill rate of at least 90%. One of the problems with an Ad Network is that many apps requesting a single advertiser's ad at once.
eCPM means "effective cost per mile". eCPM is used to calculate the ad revenue generated by a banner ad or a campaign in terms of number of impressions received in 1000s.
eCPM = (Total Earnings / Total impressions) X 1000
Companies providing Ad Network Platforms
AirPush - 2nd largest add network for android
Gruner und Jarh