After attaining unlikely success as an open platform, Twitter is demanding that third-party apps show Twitter’s stream the way the company wants them to. “You need to be able to see expanded Tweets,” Product Manager Michael Sippey wrote in an announcement on Friday afternoon. He said those features make Twitter “more engaging and easier to use.” But if Twitter squeezes too hard on third-party developers, it risks damaging something more important to the company than any set of features: It risks destroying the culture that has grown up around it.

“These are the features that make Twitter Twitter,” Sippey wrote, referring to expanded tweets. For established Twitter users and developers, that statement is hard to swallow. For one thing, expanded tweets are a brand-new product that hasn't been around long enough to have any impact whatsoever. More to the point, nearly all the features that make Twitter what it is today were invented by users dissatisfied with Twitter’s own user interface.

The reason users could do this boils down to two words: open platform. Twitter is one of the best examples of what’s possible for a large-scale, real-time tech company that opens its platform to developers. Kin Lane is a keen observer of open platforms who has been researching the business of Twitter’s application programming interface, or API. Published by Twitter, the API is a set of commands, available to anyone, that controls the company's servers, allowing outsiders to build services of their own using Twitter's inherent capabilities. 

As Sippey’s statement sank in on Friday, Lane shared his comprehensive, ongoing timeline of key moments in Twitter’s history. Read the timeline and, if you're a long-time Twitter user, recall what it was like. Early on, Twitter bent over backward to accomodate developers. The company even showcased its favorite third-party Twitter apps. The ability to build on Twitter yielded many great apps and successful businesses.

And it wasn’t just programmers building software. Twitter users themselves invented social conventions like @ mentions, hashtags and retweets, creating the manners and protocols that define the service today. Twitter took the cue, introducing features which built on practices that users invented on their own, including clickable hashtags and the native retweet button.

Cut to the QuickBar

Things started to get weird in April 2010 when Twitter acquired Tweetie, the most beloved third-party Twitter client for iPhone at the time. It began to use that first-rate mobile interface to experiment with its business model. That’s where it put the QuickBar, an irritating overlay that showed trending topics above the main timeline screen. It provoked such a backlash that Twitter pulled the feature.

Though users defeated the QuickBar, it was a wake-up call. Twitter had taken over a beloved client and started twisting it into something presumably more lucrative but less user-friendly.

Over the following year, Twitter gradually built walls around its ecosystem. In March 2011, Ryan Sarver of Twitter's platform team warned developers not to “build client apps that mimic or reproduce the mainstream Twitter consumer client experience.” That, of course, is what most of the beloved third-party Twitter apps do, more or less. While Twitter only cracked down on apps that operated on the margins of what it allowed, the tone of developing on top of Twitter changed.

By December 2011, Twitter had dispensed with Tweetie altogether in favor of its new, more consistent user interface across all its official apps. On Friday, Sippey made clear that this is the experience Twitter wants its users to have. It will release stricter rules of the road for apps “in the coming weeks,” and the company won’t comment on upcoming changes until then.

Sacrificed at the Altar of Consistency

The first major casualty of Twitter’s new stance has been its relationship with LinkedIn. On Friday, as Sippey delivered the news about “providing the core Twitter consumption experience,” LinkedIn sounded downright mournful to announce that its users can no longer automatically feed in their tweets. Twitter cut off a major hub of engagement and activity in the name of a consistent experience.

As Nick Bilton pointed out in his New York Times blog, even Twitter’s own user experiences are not consistent yet. And third-party Twitter apps like Tweetbot are beloved by users. But unless Twitter’s new rules make it possible for those apps to accomodate the changes without giving up too much of their originality, that era might be drawing to a close.

Some observers, like Bottlenose CEO Nova Spivack, think Twitter’s change is shortsighted. Spivack proposes a new business model for Twitter that’s built around the open, extensible nature of the Twitter of old. Twitter is a motherlode of valuable data, and Spivack marvels at the company’s unwillingness to charge developers to compete in extracting that value.

In contrast, entrepreneur Anil Dash is skeptical of the idea that outside developers know better than Twitter. Consistency is critical for “normal people,” he wrote. Dash is right that lots of Twitter apps are spammy and unhelpful. Twitter could probably improve its users’ lives by being more strict with such apps.

But Twitter works because people who love the service have built a culture on top of it. They use what makes them happy. In the past, people who weren’t happy with Twitter's native offering were able to build something they liked better. If Twitter breaks that ability, the nature of the relationships built on its network will change. Features aren't what “make Twitter Twitter.” People are.