Twitter used to be something like a utility, but at some point along the way it decided to become a media company. And Twitter the media company looks a lot more like Facebook than the old Twitter. What that means is that Twitter wants — needs, really — to control every aspect of the Twitter experience. That also means cutting off apps or services that compete with Twitter — particularly competing media experiences — or that pull more value out of Twitter than they put in. Which is why Twitter just changed the rules of the game for developers that build things on top of, or for, Twitter.
What does Twitter the media company look like? Well, it does things like partner with the Olympics to produce slick, curated experiences like the one pictured above — which you can expect way more of. It tries to curate and surface stories it thinks you'll be interested in with its Discover tab. It sends you newsletters. It launches a Twitter political index. It worries about policing content. It tells developers to "to build content experiences and applications into Twitter" using its new media tool, Twitter Cards. It (eventually) delivers a simple-but-rich and beautiful experience that's consistent across every app.
Oh, and it makes money by selling ads.
So, it's sort of easy for an app or service to find itself suddenly competing with Twitter. While Twitter started warning makers of client applications like Tweetbot, Echofon and Twitterific well over a year ago not to build those kind of apps (with the warnings getting more stern over time), one of the first practical indications that a newly self-confident Twitter was stretching its muscles and not afraid to kick people in the face in the process was when it cut off access to LinkedIn, followed by Instagram. It cut off LinkedIn because Twitter got nothing out of having its content displayed there and it cut off Instagram because it didn't want the now-Facebook-owned service to have access to Twitter's invaluable follow and interest graphs.
It's a (very) safe bet that Tumblr — essentially a rival social network-turned-media company — is next to lose access to Twitter. Currently, when you sign up, Tumblr offers to poke through who you're following on Twitter, giving it access to your follow and interest data. This is data that Twitter does not want it to have, particularly as they've effectively both become media companies. (Update 5PM EST: Tumblr's Twitter connection has disappeared since the above screencap was taken last night. It's not clear who cut the cord, or precisely when though I suspect it's since the piece was published. No comment yet from either side. Update 7:33PM: Tumblr confirms Twitter cut off its access to users' friend list.)
Which is also one of the core reasons it's another (very) safe bet that Flipboard will also lose Twitter access soon. Most of the attention paid to how the Twitter rule changes will affect "social reading" apps like Flipboard, Prismatic and Zite has focused on how these apps violate Twitter Display
Guidelines Requirements — things like "tweets that are grouped together into a timeline should not be rendered with non-Twitter content" and that "no other social or 3rd party actions may be attached to a Tweet." Which is true — these apps will have to change the way they display Twitter content to continue to have access to it. But Flipboard, by far the biggest of the bunch — it even signed a deal with the New York Times — does a great many things to annoy Twitter, particularly when taken as a whole. Namely, Flipboard uses your Twitter (and Facebook) network to seed its own (albeit passive) social network and it sells its own advertisements against content that it's pulling either from or via Twitter. On top of that, Flipboard's now more directly competing with the kind of event-oriented social media experience that Twitter is looking to deliver — just check out its curated Olympics page, which is in the same vein as Twitter's. So the question is not whether Twitter's going to cut Flipboard off, it's simply when: Will it wait until the new rules kick into place in six months? Or will it go after Flipboard sooner, with the ensuing election news extravaganza coming up? Hrm.
The line between ecosystem partner and competition isn't always so cut and dried, though, as even Instagram shows. Even though Twitter's since cut it off from access to Twitter users' followers, Instagram was one of the first services to use Twitter Cards — the fancy way Twitter displays things like YouTube videos, news stories from selected outlets and photos, and now the Twitter-preferred way for "developers to build content experiences and applications into Twitter." Instagram still hooks into Twitter very neatly — when you tweet from Instagram, it looks nice — partly because of Cards and partly because of Instagram's use of the @username convention.
One of the more obscure new Twitter provisions are the requirements that the "@username must always be displayed with the '@' symbol" and that they must "link @usernames to the appropriate Twitter profile." This has mostly been taken to mean that awesome tweet-aggregating sites like Favstar.fm can't link internally anymore, and have to link out to Twitter whenever they use an @username. (Update 6:30PM EST: Twitter clarifies — Favstar (and others) do not have to link out to the user's Twitter profile directly, but it can link to "internal profile for the user within [its] app. That profile must have a link back to the user’s profile page on Twitter.com," per the footnotes here.") But read more closely, the intention of this guideline becoming a requirement is for Twitter to take more complete ownership of the @username convention in its entirety — to make it abundantly clear that it's a Twitter thing, and to make a person's @username totally canonical as a form of identity. In other words, Twitter wants @mattbuchanan to not just link to Twitter, but to mean me on Twitter, even if it's interpolated by another app or service. The problem, in part, is that if my friends or I have different @usernames on Instagram — particularly if we push those Instagram photos to Twitter — it breaks that convention, its meaning, and dilutes "the Twitter experience." In other words, don't be shocked when this tiny provision has far-ranging consequences for other apps and services, though it's not clear exactly how Twitter's going to go about sorting it out.
The thing about @usernames isn't entirely obvious, and it's only one of a number of ambiguities in the new rules. But that's fairly intentional. Twitter's not going to kill any apps or services that it actually likes, doesn't see as much of a threat or that it thinks adds value to the Twitter ecosystem, even if it looks like it's breaking the rules. So Prismatic and Rebelmouse may escape scrutiny, if only for a time, while Flipboard and Tumblr should get sniped relatively quickly. And in general, if Twitter product team director Michael Sippey named an app or service in this recent blog post, it's safe for now, though it may need to tweak things — Favstar.fm and Klout, for instance, will probably have to change the way they display tweets and links because Twitter wants to have complete control over how every piece of Twitter content is shown, all the way through. (You know, like a media company.)
Still, the consequences of Twitter slowly illuminating what its rules really mean sucks for a lot of developers. It's easy enough to say that the One Rule to Rule Them All is, "Don't compete with Twitter." Which is fine and dandy, because it's all for the greater good of Twitter or whatever. The problem is that it's real easy to be a valuable, contributing member of the ecosystem today and then tomorrow find out that you're now competition waiting to be crushed. Just ask the Twitterific guys.