[caption id="attachment_6441" align="aligncenter" width="561"] Instagram might maintain its Twitter profile, but it's disabled photo integration with Twitter itself.[/caption] Back in April, Facebook CEO Mark Zuckerberg slapped down a cool $1 billion for Instagram, a photo-sharing network. At the time, some tech pundits insisted that Zuckerberg had overpaid for the service—perhaps grievously so. Others thought the acquisition was a solid move, a way for Facebook to strengthen its photo capabilities ahead of its IPO. Whatever one’s opinion, it’s become increasingly clear over the past few days that Facebook wants to transform Instagram into the latest example of a “walled garden,” a closed-off ecosystem with limited interaction with other services. “Instagram has disabled photo integration with Twitter. As a result, photos are no longer appearing in Tweets or user photo galleries,” read a Dec. 5 note on Twitter’s Status page. “While tweeting links to Instagram photos is still possible, you can no longer view the photos on Twitter, as was previously the case.” According to unnamed sources speaking to The New York Times last month, Twitter was already working on a photo-sharing service similar in many respects to Instagram, including the use of filters. (Other social networks are also muscling up on photo features: among Google’s recent announcements was Snapseed, an Instagram-like app for mobile devices.) At the recent Le Web conference in Paris, according to CNN, Instagram CEO Kevin Systrom said that other services wouldn’t suffer the came cutoff as Twitter. “This is more of a one-off,” he reportedly told the audience. That move came just as Instagram launched a Web-based platform with user profiles, a significant brand expansion beyond mobile devices. Many pundits, of course, aren’t happy with this latest turn of events. “The only way these companies can succeed financially is by tricking members and forcing them into walled gardens,” Dan Lyons wrote in a Dec. 10 ReadWrite posting. “Think of it this way—there’s a reason that they don't hold a circus out in the open, and instead put it under a tent—and it’s not to keep you dry in case of rain.” Executives like Systrom, Lyons added, must necessarily serve two masters: investors and users. The latter wants relatively open systems with lots of interoperability—how else can you post that photo of your cat, run through a cheesy 1970’s filter, to as many social networks in as little time as possible. But the former, who hold the money, want a significant return on investment; and sometimes, the model necessary to generate that investment centers on building the walls around that garden as fast as humanly possible. Facebook boasts a billion users, give or take a couple million. While that makes it the largest social network out there, it faces challenges from a number of rising challengers, most notably Twitter. “While Facebook and Twitter continue to be among the most popular social networks,” read a report from Nielsen and NM Incite earlier this month, “Pinterest emerged as one of the breakout stars in social media for 2012, boasting the largest year-over-year increase in both unique audience and time spent of any social network.” Even as Twitter, WordPress, Pinterest and other social networks enjoyed double-digit growth in the U.S. over the past year, Facebook has seen its unique visitors decline by 4 percent among PC users. That’s a potentially worrisome trend for Facebook, especially as it seeks ways to monetize its presence on mobile devices and assure Wall Street that it can deliver revenue growth over the long term. In light of that, it’s no surprise that the social network would try to constrain its biggest rival’s growth by cutting off interoperability with Instagram—that inevitability aside, it’s no surprise that such a move is drawing shrieks from advocates of a more open Web.   Image: Twitter