Outtake: 
At its heart, Twitter is a firehose. Everything you tweet shows up to every one of your followers. It’s what makes Twitter feel like the real-time pulse of the world. But it could also be preventing Twitter from growing. Follow too many people, and you lose track of those you love and stop following anyone new.
Imagine you’ve just joined Twitter. You follow some popular accounts of big publishers and celebrities you’re interested in, as well as some friends and acquaintances. The unfiltered feed works. You get up-to-the-minute news and stay aware of what people you know are up to. There aren’t so many tweets in your stream yet that you miss the ones from the people you care about most.
But then you follow a few more people, and then a few more. You find more distant acquaintances and colleagues on Twitter so you follow them. You subscribe to experts in the niche areas you geek out about. Friends retweet something funny and you follow the author. Or somebody random @ replies and follows you so you do the polite thing and follow back.
Gradually, your feed gets noisier and noisier. A few...