Blogger was launched in summer 1999 by Pyra Labs, co-founded by Evan Williams who is now CEO of Twitter where he works alongside Biz Stone who also worked on the development of Blogger.
In 2003, Pyra Labs was acquired by Google for an undisclosed sum, which proceeded to open up Blogger as a completely free service, allowing users to upload and share photographs.
The acquisition proved to be a boon to Google, which began serving its AdSense ads on the millions of user-generated blogs.
In May, blogspot.com subdomains were visited by 52m people in the US, nearly double its closest rival Wordpress, whose blogs were viewed by 28m.
About two-thirds of Blogger traffic comes from outside the US, mainly from Brazil, Turkey, Spain, Canada and the UK.
Google said Blogger has been instrumental in helping Iranians report from the frontlines of recent protests over Iran's presidential elections, .