Five years ago, according to Twitter, co-founder Jack Dorsey sent out the first tweet: "inviting coworkers." Ev Stone tweeted for the first time within a minute: "just setting up my twttr."

Co-creator Dom Sagolla had it right when one of his first tweets that day predicted, "oh this is going to be addictive."

The anniversary has prompted a number of analyses and retrospectives:

9 Newsworthy Twitpics That Captivated the World - Mashable
> Five years since the first tweet: a Twitter revolution in breaking news - Frontline Club
Happy 5th Birthday, Twitter! 10 Top Tweets of the Past 5 years - ABC News
The history of Twitter, 140 characters at a time - The Globe and Mail
Twitter: tweeting louder than ever - The Guardian
Twitter at Five: Bringing out the worst in journalists - National Post
> How Twitter changed our media habits - The Media Blog
Happy Fifth Birthday Twitter! Five Milestones from the Past Five Years - AllTwitter
#numbers - Twitter Blog

And of course, Twitter itself is bustling with people talking about Twitter: