In recent years, many Xooglers(that’s what former Googlers call themselves) left Google and went on to start-up new businesses and made headlines everywhere. Some of the companies were acquired by Google and the founders started working for Google again. 
We have compiled a list of Top 15 Companies Founded by Xooglers. There are certainly many more ex-Google entrepreneurs out there, so let us know of the ones who have caught your attention in the comments below.
15. AppJet
Two of the three founders of AppJet were Google engineers. And since Google acquired AppJet an year ago, they’re working for Google again. The team, which created real-time document collaboration software called EtherPad, joined the now deceased Google Wave group.
14. Hawthorne Labs
Apollo is a newspaper for the iPad. It’s just one of the products from startup Hawthorne Labs, and features an algorithm that learns what articles and sources you enjoy, and helps you discover new content based on your personal preferences and viewing history. Co-founder Shubham Mittal previously worked for both Microsoft and Google.
13. Aardvark
Another startup founded by ex-Googlers, only to be acquired by Google, Aardvark takes your questions and finds people in your own social network to answer them. Instead of spamming your inquiries to all of your online friends, which you could do without any help, Aardvark finds the friends and the friends of friends who are most likely to have the answer.
Google paid $50 million for the company in February 2010, the service is still a Google Labs project but it could become an integral part of Google Search or Android.