Twitter has blocked and restrict its services to some social network from piggybacking on Twitter's social graph.
On December 5, 2012, Twitter users are experiencing issues with viewing Instagram photos on Twitter. This issue is explained in Twitter's status post, saying that "it is due to Instagram disabling its Twitter cards integration." As a result, photos are cropped and being displayed using a pre-cards experience.
Instagram previously supported Twitter cards "because we had a minimal web presence" - the app only existed on mobile phones, and it was difficult to find photos via the web. Instagram is no doubt still smarting after Twitter stopped letting its users collate Insta-friends using their Twitter contact lists.
Speaking at the LeWeb conference in Paris, Instagram's Chief Executive, Kevin Systrom, insisted that although "we will always be integrated with Twitter in a way that you can tweet out from Instagram to Twitter", there were changes being made to the connections between the two services - though he denied it was anything to do with Instagram's acquisition by Facebook earlier this year. He also denied that it was linked to Twitter's blocking of access by Instagram users to the Twitter social graph, used to find friends of people who join the service.
Although the ability to tweet a photo as user posts it on Instagram isn't going away - it's just not going to look as good to Twitter users as it will to Instagram users.
With Facebook supporting Instagram, it is developing a more web-based interface that supports Facebook "likes".
Twitter benefits from having content from other media-generating services - such as Instagram. In September, it is reported that user engagement from Twitter to Instagram pictures was greater than within Instagram itself.
Twitter has also blocked services such as LinkedIn and Tumblr from accessing its API and especially from getting details about users on its service since August.
Twitter's decision to restrict its services to other social networks is because it is preventing its potential rivals from expanding quickly by building on Twitter's social graph. Although it is smaller than Facebook, Twitter has positioned itself in the social network space where it is able to create more active users in a wider area, making it a more valuable social network for people that wants to connect easily. And more active users means more attention to paid ads.
Meanwhile, Twitter is reported to be working on Instagram-like photo filters - a project that would let the microblogging service to catch up with Instagram.