Seven years ago today, Twitter founder Jack Dorsey sent out his very first tweet which signaled the official launch of the microblogging website. Today Twitter is a global phenomenon with more than 200 million users worldwide responsible for pushing some 400 million tweets each day. To say the site has come a long way would be the understatement of the year.

The social networking site has had countless milestones over the past seven years. The idea for the hashtag came about in 2007 courtesy of Chris Messina and was first used in a high-profile instance by California resident Nate Ritter to chronicle his frequent posts about the October 2007 wildfires in San Diego County. We also witness the first retweet that same year.

Oprah Winfrey famously joined the site in 2009 and just a year later, Mike Massimino sent the first ever tweet from space. In 2010, the World Cup helped to unite a global audience and in 2011, the service was instrumental during the 8.9 magnitude earthquake and resulting tsunami that slammed into Japan. Just last year, Twitter was a driving force behind the summer Olympic games in London, the Grammys and even President Barack Obama's re-election.

In a post on the company's blog celebrating the occasion, editorial director Karen Wickre said the site has become a true global town square - a public place to hear the latest news, exchange ideas and connect with people in real time. It's where you come to connect with the world at large, she said.