"In a platform that's social by nature you have to do this in a disciplined way," he said.

Interestingly, Horowitz spoke about Google's OpenSocial development tools in the past tense, saying that the project wasn't as successful as it could have been because it came at a time when the company lacked a compelling, "exemplary" social networking site.

OpenSocial is -- or was -- a set of common APIs for building social networking applications that Google designed so that developers wouldn't have to write the same application from scratch multiple times for different sites.

Launched in 2007, the OpenSocial APIs were used by a number of social networking sites, including MySpace, but Facebook didn't adopt them, opting to stick with the ones it had by then developed for its massively successful application platform.

Google didn't immediately respond to a request for comment regarding the status of OpenSocial, but based on Horowitz's comments it seems fair to guess that Google is developing a different API toolset for Google+.