That Twitter is abandoning its developer-friendly roots is a secret to no one. Whether the controversial strategy will preserve the network and help it make money — or destroy it altogether — remains a mystery.

Wednesday, the information network followed through on its long-public plan to restrict app makers’ access to its data. The victim this time around is Tumblr, a potential threat to Twitter because of its size and popularity. Twitter stripped Tumblr of its rights to help Tumblr members find their Twitter friends on the blogging platform, citing the value of its network as the reason for doing so.

Not a one-off instance, the move has been described as a hostile attack on a partner. Others have called it a necessary, evolutionary step by Twitter to ensure that it maintains its hold over the individual relationships that it can sell to advertisers. It comes down to the value of what Twitter calls its “follow graph”: The data that maps the massive network of connections formed by Twitter users following other Twitter users.

The one consensus everyone shares is that Twitter will strike again — and soon.

Who’s Twitter’s next target? And at what point will Twitter’s decision to protect the perceived value of its connections backfire? Is Twitter actually competent enough to innovate without the support of developers?

The competency hearing is now being held in the court of public opinion, with developers and users testifying against — or in defense of — the information network’s decision-making capabilities.

A question of value

“There’s great value associated with Twitter’s follow graph data,” Twitter said in a statement earlier this year when it blocked Instagram. In July, the company cut off Instagram’s access to the “Find Friends” piece of its API.

When we asked Twitter for an explanation of its actions against Tumblr, a spokesperson pointed us to the same statement. What the statement actually means is open to interpretation.

Some believe that Twitter sees its follow graph as more essential to the company’s financial well-being than the content that members create.

Simply put, the graph is greater than the tweet.

User interface designer and Svbtle creator Dustin Curtis has broken down the logic behind this philosophy. In a post entitled “Black Widow,” Curtis details that Twitter’s follow graph hinges on interests. On Twitter, as opposed to Facebook or other networks where relationships with friends and family are tantamount, people consume the content of their favorite celebrities, personalities, and companies.

These person-to-interest correlations are of great value to advertisers because Twitter can mine data from the follow graph to find people whose interests are aligned with a advertisers’ messages.

“People use Twitter more like they use TV … they consume the content as a form of entertainment,” Curtis said. “Normal people have very little incentive to use Twitter except to communicate with their interests.”

Previous research and Twitter’s own statements support Curtis’s conclusions. Just 15 percent of the adult American online population use Twitter, according to Pew Research. Of those that do actively use the information network, some 40 percent don’t tweet, Twitter CEO Dick Costolo said earlier this year.

Extrapolating further, Curtis surmised that the ordinary Twitter user has no reason to use the information network beyond consuming content. This means that if a person can find their celebrity connections on a competing network, say Tumblr or Instagram, they may lose interest in Twitter.

Ergo, the graph is the thing of most value to Twitter. It can seemingly afford to make enemies, but it can’t afford to give away connections to Instagram and Tumblr because then it would lose its appeal to advertisers.

“I’m the least surprised person,” entrepreneur Dalton Caldwell told me. “This is what I was saying a month ago.”

Caldwell is the creator of App.net, a for-charge, utopian social platform that looks to be the open communications framework that Twitter once was. Caldwell’s creation was inspired by what Twitter could have been: a real-time cloud API company. Instead, Twitter chose the divergent path and opted to become a media company, he argues. In so doing, protecting its prized possession becomes critical.

“What [Twitter is] doing is rational,” he said. “They’re trying to protect what their actual value is. The social graph is that value.”

Wednesday’s move to block Tumblr’s access to its graph is one of the logical outcomes of Twitter being a media company, he said.

On the backs of others

The issue, as developers see it, is that Twitter has been lifted to greatness through the help of an enthusiastic developer community and passionate members.

“Many of the things that are ‘Twitter’ weren’t invented by Twitter,” Michael Heilemann, the interface director at Squarespace, observed in a debate about why people are upset at Twitter.

As Heilemann pointed out, mentions and hashtags were inspired by the symbols early users took upon themselves to add to the tweet stream. Core experiences including search and mobile were developed outside the company and then acquired and woven into the Twitter we know today.

In shifting course from an open to a closed network, Twitter is shutting out the very developers that gave the network value in the first place.

“The problem with this solution is that Twitter was built on the backs of the very developers it is now blocking,” Curtis said. “It now expects those developers to continue supporting Twitter by syndicating content into its platform, but it no longer wants to provide any value to developers in return. This is an extremely dangerous position because it creates resentment in the minds of the people most likely to influence the future.”

The gamble

The information network now wants to go it alone. The company is leaving behind its small-time friends for big-city fame and fortune, and it’s not just pushing away one-time friends. It’s making enemies.

“If Twitter cuts off Instapaper’s ‘find friends’ access, I’ll probably remove all Twitter functionality. It’ll hurt, but it’ll feel right,” Instapaper creator Marco Arment said yesterday on Twitter.

Fine by Twitter.

Twitter is betting the company on its own capability to keep the innovation alive and prevent its more than 140 million active users from migrating away to other networks. It’s a risky gamble, because the company has yet to prove it is competent or capable enough to do just that.

Twitter Cards, or expanded tweets, are perhaps Twitter’s most innovative original development in recent years. Cards keep Twitter users engaged with photos, articles, and video from external sites embedded within the tweet stream. And yet the Cards product relies on publishers’ and app makers’ willingness to integrate with Twitter. That includes Tumblr, but for how much longer?

“Given our history of embracing their platform, this is especially upsetting,” a Tumblr spokesperson said Wednesday. “We eagerly enabled Twitter Cards across 70 million blogs and 30 billion posts as one of Twitter’s first partner.”

Should Twitter lose the support, confidence, and trust of partners, the company could face a bigger backlash that not only erodes the value of competitors’ apps but the value of its own network. Still, it’s a risk the information network appears quite content to take.