Mobile ad network AdMob is celebrating its third birthday. Since the company was incorporated in 2006, AdMob has grown from one employee, Founder Omar Hamoui, to more than 100, working in seven offices worldwide. During that time mobile Internet usage has grown massively, and there are now more than 49 million mobile web users in the US alone each month.
To celebrate the occasion, AdMob has produced a few stats showing what the company has achieved in the last three years:

• 75 billion ads served
• First company to offer a self-service mobile advertising network
• 100 million unique mobile users reached worldwide each month
• First to create unique iPhone and rich media ad units for mobile
• 12.7 million iPhones and iPod touch devices reached in March 2009, approximately one in three of the devices worldwide
• 7,000 mobile Web sites live on AdMobs network
• 1,418 iPhone apps sent AdMob an ad request in March, including 33 of the top 100 free applications
• Drove 230,000 downloads of iPhone applications through the AdMob Download Exchange in less than a month

Theres more on the AdMob blog.