Developers working on client applications that replicate Twitter.com's basic user functionality should turn their efforts elsewhere, because the company doesn't want any more such apps on the market.
Moreover, developers of existing client applications should brace for stricter enforcement of terms and conditions, as Twitter strives to make the overall user experience more uniform and of higher quality.
"Developers have told us that they'd like more guidance from us about the best opportunities to build on Twitter. More specifically, developers ask us if they should build client apps that mimic or reproduce the mainstream Twitter consumer client experience. The answer is no," Sarver wrote in a post titled "Consistency and ecosystem opportunities."
"If you are an existing developer of client apps, you can continue to serve your user base, but we will be holding you to high standards to ensure you do not violate users' privacy, that you provide consistency in the user experience, and that you rigorously adhere to all areas of our Terms of Service," he added.
Twitter has also modified its developer terms accordingly and provided more details about this topic in that document.
Responses to Sarver's post have so far been mostly negative.
"All third party Twitter developers, no matter what they make, are now walking on eggshells, constantly at risk of
offending Twitter's ideas of how users should interact with Twitter," wrote one developer, echoing similar sentiments from others commenting on the discussion thread.
Reached via e-mail, Duane Roelands said he is now discouraged from further enhancing his Twitter client application Quitter, which he had considered upgrading with support for international characters.
"In light of Mr. Sarver's announcement, it seems like a waste of time. Why would I invest time and effort in enhancing an application that Twitter is going to disallow? There are no clear and concise guidelines that I can use to determine whether or not my client is going to run afoul of the new rules," said Roelands, lead developer for Akcelerant Software in Malvern, Pennsylvania.
Tensions between Twitter and its community of third-party developers have been worsening over the past 12 to 15 months, when Twitter started taking a more active role in building out its previously sparse menu of native features.
For the first four years or so of its existence, Twitter relied heavily on -- and encouraged -- external developers to provide extra functionality around its bare-bones microblogging service.
During that time, Twitter, founded in 2006, had its hands full keeping up with the basics of running the company, such as maintaining the site up and available, a notorious struggle for years.
Thus, developers have created hundreds of thousands of applications for Twitter, including desktop clients, mobile interfaces, search engines, photo sharing tools, monitoring and analytics software and profile customization tools.
Many of these developers, which range from individual freelancers to large outfits, have built businesses of various sizes around their Twitter applications.
But starting in late 2009 and very clearly ahead of its Chirp developer conference a year ago, Twitter, having grown its staff and business significantly, has made it clear that it intends to provide by itself or in exclusive partnerships whatever functionality it considers of core importance to the Twitter user experience.
That now includes official Twitter applications for the iPhone, BlackBerry, iPad, Windows Phone and Android devices, for example. "As a result, the top five ways that people access Twitter are official Twitter apps. Still, our user research shows that consumers continue to be confused by the different ways that a fractured landscape of third-party Twitter clients display tweets and let users interact with core Twitter functions," Sarver wrote in his post.
So over the past year, Twitter has become a competitor for some of its external developers.
"There was a time when Twitter's attitude towards the developer community was: 'Hey, we've built this really cool platform and this really cool API! We can't wait to see what really cool things you build with it!,'" said Roelands.
That led to the creation of myriad Twitter applications, which in turn helped spur Twitter usage.
"Twitter appears to have decided that the developers who were once their allies are now a threat to the company's long-term plans. It's a shame," said Roelands , who also created an open source .NET library called TwitterVB that lets developers write Twitter applications without having to know the inner workings of the Twitter API.
However, some developers think the real issue is that Twitter, with its new focus on aggressively growing its revenue ahead of a possible initial public offering (IPO), now finds that having third-party Twitter client applications could dilute its ad revenue generation efforts.
"Twitter is under enormous pressure from its investors to raise revenue in time to take advantage of the IPO window opening up for social networking sites. Unfortunately, there are signs that Twitter views third party developers as competitors for their ad dollars," said Adam Green, a Boston-based Twitter developer, whose applications include 2012twit.com, a Twitter dashboard for the 2012 Presidential election.
Roelands holds a similar view. "Twitter's ability to make money in the future is going to be about getting as many ads as possible in front of as many eyeballs as possible. Every person using a non-Twitter client is a person who's probably not going to see those ads. Ergo, Twitter wants to be able to shut those clients down if they so choose," Roelands said.
Instead, Twitter should nurture developers, because their success will in turn help Twitter, Green said. "Twitter should make it an integral part of its business model to turn the third party into business partners. When third party developers make money, Twitter should make money, and vice versa," he said.
Still, Sarver maintains that plenty of opportunities exist for third-party developers in the Twitter platform.
As examples of developers who are taking advantage of existing opportunities, Sarver cited SocialFlow's publisher tools, Klout's application which crunches Twitter data to generate individual reputation scores and HootSuite and Seesmic, which let businesses monitor their brand mentions on Twitter and act accordingly.