, a major Facebook rival, was quick to jump on the issue.

Early Thursday, Vic Gundotra, Google's senior vice president of social business, in a , said Google is working to avoid "screwing over developers."

Taking a swing at Facebook in the wake of Caldwell's letter, Gundotra focused on his decision to not open the Google+ application program interface (API).

"I get a lot of heat for not releasing a full write API for Google+," he wrote. "When we open an API, we want developers to feel confident that the innovations they build are going to be long lasting. Releasing an API, and then later changing the rules of the game isn't fun for anyone, especially developers who've spent their life's energies building on the platform."

On the heels of Caldwell's letter and Gundotra's post, was a Facebook statement to the U.S. Securities and Exchange Commission that 83 million of Facebook's users are fake.