Twitter is celebrating its seventh birthday today with a video showcasing its greatest moments so far, from the first tweet in space to the first tweet by Oprah. 

It's fun to trace its origins from humble startup to worldwide blogging platform. It's also hard to imagine it's come so far since its launch on March 21, 2006. Back then, the first tweet heard round the world was from founder Jack Dorsey, who wrote, "just setting up my twttr." Now the service boasts "well over" 200 million active users who generate nearly 400 million tweets per day. 

Check out the video below and tell us how you think Twitter's evolved in the past seven years. 

[via Mashable]