Kim-Mai Cutler's history of Instagram includes the wonderful photo above.

The following line really shouts to me:

COMMUNITY: GUARD THIS ASSET

Community is the unsung hero in scaling Instagram (and Tumblr!)...

Instagram had as many community managers as engineers.

It's true for Tumblr, too.

I'm not even sure what a community manager does for Instagram and Tumblr, but I'm guessing they:

• Curate the best content being created. Instagram and Tumblr are metaproducts that get other people to work for them. Community managers pick the best content to feature -- in Instagram's case for the Popular tab, in Tumblr's case as Featured items. Being featured gets the best users extra props and follows, which makes them want to create more content.

• Encourage good user behavior. Give props, reblogs, and follows to the best users. Delete bad content and bad users.

• Manage the company's social media. You wouldn't believe how much work it is to maintain PandaWhale's Twitter, Tumblr, and Facebook presences, and I haven't even created Pinterest and Instagram accounts for us yet! This is even harder once you're actively listening to user feedback, answering customer support questions, and actively replying to people on the website, too!

Well, now that I think about it, that's a lot!

My other favorite part of Kim-Mai Cutler's article is her paragraph about user experience:

With their UX skills, Krieger and Systrom refined Instagram to require as few actions as possible. Unlike the original version of Path, Instagram didn’t force users to add tags about people or places to their photos. A photo could be posted in as few as three clicks. Mirroring Twitter, they made Instagram public by default.

It's really, really hard to make things simple.

Arguably, all Instagram did was copy Hipstamatic and let you share on Twitter, Facebook, Tumblr, Flickr, and Foursquare.

They took what existed, and made it social.

Having said that, it's really, really hard to make things simple.

And to know what problem to solve.