Facebook on Monday announced the appointment of Chief Operating Officer Sheryl Sandberg to become the first female on the company’s board of directors.

In announcing the appointment of Sandberg, Facebook founder Mark Zuckerberg said that “Sheryl has been my partner in running Facebook.” “Her understanding of our mission and long-term opportunity, and her experience both at Facebook and on public company boards makes her a natural fit for our board,” he added.

Facebook also changed the default email used to contact its users through the site.

The email change to the little-used @facebook.com addresses that the social networking site provided to all its 900 million users could prompt a new backlash against the company since it failed to warn users in advance about the change.

A Facebook spokesperson told CNN that the switch had been introduced to ensure consistency of communications for all the site’s users.