Google announced creation of a new publicly traded company, named Alphabet, under umbrella of which Google is “hosting” its multiple businesses.

It is announced that Alphabet will be run by Larry Page and Sergei Brin, who are co-founders of Google.  The new CEO is Sundar Pichai. Google will become one of the companies of Alphabet. Alphabet will be a conglemerate of companies, while Google will only be responsible for their internet business, including Android operating system, Chrome browser, YouTube and of course, search.  As Larry Page mentions, this will allow Goolge to become more flexible, running different businesses independently.  Page is leaving internet and advertising business to Pichai.
Google-Alphabet
Pichai was responsible for Google, now he will add YouTube with YouTube CEO Susan Wojcicki reporting o him. Other experienced CEOs will run different businesses, with assistance from Page and Brin.

Google thinks that this new structure will allow to keep focus on tremendous opportunities Google has in its other businesses.