Crossrider's application, which is free, just adds an icon to Google+, where users can view their Facebook pages.

"It's a site within a site," Menachemi said, adding that the company would be willing to make improvements. "If users want a feature to post updates on both networks, we will. If they want to comment on their Facebook screen, we will do it."

He noted that the popularity of the Google+Facebook application has been higher than expected. "We didn't do any PR. It was just one tweet and one Facebook share and people picked it up," Menachemi said.

Still, there has been some criticism of the application on Crossrider's own website, with some comments calling it "malware" — or malicious software.

Menachemi denies that Google+Facebook is malware but has no plans of removing the negative comments from the Crossrider site.

Menachemi, a former chief technology officer at financial news and analysis site Seeking Alpha, founded Crossrider a year ago along with Shmueli Ahdut — the developer of Google+Facebook.

The company provides a framework for developers to come up with new features for browsers. Menachemi said the Google+Facebook application was created to show the capabilities of Crossrider.