In its earliest iterations, the idea behind Twitter was to mimic the status updates many of us set on our instant messaging clients. Twitter essentially extended those personal updates to cell phones via SMS. Obviously, the idea grew from there. But that early idea — focusing on mobile devices — is an absolutely essential part of Twitter’s strategy as the company announces plans to go public. One of Facebook’s key challenges following its IPO was to prove that it could be a mobile company. By the time Twitter goes public, mobile will clearly be its home turf. And there’s something else about those early days that proved to be key to Twitter’s rise: The limits of an SMS message. Because people could only send messages that were 140 characters, the service was much more inviting and accessible.

+ The New Yorker’s Matt Buchanan on the Twitter of tomorrow.

+ Brad Stone: The Accidental Revolution Hurtles Toward Payday.

+ Last night, I Tweeted that Twitter would have a bigger marketcap than Facebook within 3 years. It’s a longshot. But The Street’s Eric Jackson decided to extend the idea and explain how it might happen.

+ “There were a few minutes of clapping, high fives and private calculations of net worth. Then we all went back to work.” Hunter Walk reflects on Google’s IPO and what going public could mean for Twitter.