I think that pretty much from the beginning there existed a tension between users and software developers around the notion of interoperability. Users want it while developers more often than not view it as a threat to their strategy to lock users into their apps and services.
With social networks the tension has increased because users simply don’t have the bandwidth or desire to manage multiple networks, which only fuels the developer fears that interoperability is a threat so the way to win is to run faster on the hamster wheel to develop more features and services which will drive users to their service and quench the desire for competing services.
Users still want interoperability whether in the form of directed services like identity and interoperability or more strategic features like messaging.
I noticed something with the latest version of TweetDeck that demonstrates how interoperability is good for users and for developers. The integration of Facebook alongside Twitter has, for me, resulted in my re-engagement with Facebook on several levels. Not only am I actively monitoring messages in Facebook as a result of the added feature pane in TweetDeck, but I’m an “retweeting” Facebook status messages to Twitter. Here’s a screenshot from my rig (in the interest of privacy, I removed my direct messages pane).
Lastly, I find it really interesting that desktop client apps are taking a leadership position in driving service engagement and now interoperability. I wrote last year about how desktop and mobile “satellite” apps were changing the way I use popular services, I’m more convinced than ever that developers have to court this trend as a central strategy for consumer AND enterprise users.