One of the key differences between Google+ and rival social networking sites like Facebook and Twitter is the lack of extensibility for developers. Facebook's Open Graph API has — for better or worse — made sharing even more effortless than it was before, while Twitter's API has led to the creation of apps like Tweetdeck to deep integration into a number of other services. Currently, the only tool for external developers outside of the Google+ site is the sharing badge; this this could change though with new efforts from the Google+ Developers team, which is hosting weekly "office hours" encouraging coders to explore the potential of the +Platform. Could it be that this extensibility is what Google+ needs to be more widely adopted?
Google+ developers page launched, is an API on the way?
Google+ has launched an official developer page, intended to foster innovation on the Google+ Platform.