Milestones: Foursquare To Hit 4M Users This Week, AdMob Serves 300 Billionth Mobile Ad

We’ve seen two announcements today that mark milestones for two companies we follow closely here at MMW.  Foursquare is expected to hit 4 million total users this week, and AdMob announced it’s served its 300 billionth mobile ad since getting started way back in 2007.

Foursquare reached the 3M user mark only 50 days ago, indicating that the startup is adding close to 20,000 users per day at this point.  This is upsignificantly from the estimated 15,500 users per day the company posted when it hit 3 million members a short time ago.  Bottom line is the company is still growing very quickly, much quicker than its once equal counterpart Gowalla — which is still under the 500,000 user mark as of September.

As for AdMob, the now Google-owned mobile ad-network has served 300 billion ads since its humble beginnings over three years ago.  Still showing impressive growth, the network added another 100 billion ads since May, when it posted its 200 billionth ad-served milestone.  To put it in perspective, it took nine months to get to 200 billion ads from 100 billion in August of 2009, and only 5 months to get to 300 billion today.