As Facebook's recently launched competitor Google+ is raging ahead with 25 million unique visitors so far, Randi, Facebook's marketing director and sister of its founder Mark Zuckerberg, has decided to leave and start her own social media consulting firm called RtoZ Media.

In her resignation letter which was published by AllThingsD, Randi Zuckerberg said: "My goal is to launch my own innovative programming and work with media companies to develop their programming in new, and more social ways."

She also extended her gratitude towards the Facebook team stating: "I am thankful for the strong mentorship, guidance, and support, which is empowering me to follow my dreams and show that you don't have to be an engineer to be a hacker".

Randi Zuckerberg was on maternity leave for three months prior to tending her resignation.

In her tenure, she was quite a visible face at Facebook having handled some high-profile projects like the ABC News and Facebook Presidential Primary debate in 2008, CNN/Facebook Inauguration Partnership in 2009, ABC/Facebook Live Election Night Coverage in 2010, Davos/Facebook partnership which brought the World Economic Forum to millions and the launch of Facebook Live which presented a Townhall with President Barack Obama in 2010.

She was recently nominated for an Emmy award for live coverage of election in partnership with ABC in 2010.

Randi holds a bachelor's degree in psychology from Harvard University. Prior to joining Facebook she worked at Forbes as part of the news show, "Forbes on Fox" and authored the book "Spark Your Career in Advertising."

She has also appeared on Good Morning America, The Today Show, France 2 and World News. She recently represented Facebook as a correspondent for CNN's Inauguration Day, State of the Union and on Michael Jackson Memorial live broadcasts.

Randi's decision comes at a point when Google announced its social platform, the Google+. It is reported that the new social endeavor from the search giant has garnered 25 million unique visitors as of July 24, a milestone which has been reached faster than Facebook and Twitter according to comScore. It has currently about 10 million registered users. In the light of this update, Facebook is now facing a formidable challenge, thus, Randi's departure will come as a blow to Facebook.

Randi's most recent tweet states: "Thanks everyone for the incredible outpouring of support and enthusiasm for my next adventure. So grateful. More info coming shortly!"