Serena Williams announced her plan to retire from tennis this week. Her friend and fellow Grand Slam champion Rennae Stubbs weighs in on what her farewell means for the sport and culture. » Subscribe to MSNBC: http://on.msnbc.com/SubscribeTomsnbc About: MSNBC is the premier destination for in-depth analysis of daily headlines, insightful political commentary and informed perspectives. Reaching more than 95 million households worldwide, MSNBC offers a full schedule of live news coverage, political opinions and award-winning documentary programming -- 24 hours a day, 7 days a week. Connect with MSNBC Online Visit msnbc.com: http://on.msnbc.com/Readmsnbc Subscribe to MSNBC Newsletter: MSNBC.com/NewslettersYouTube Find MSNBC on Facebook: http://on.msnbc.com/Likemsnbc Follow MSNBC on Twitter: http://on.msnbc.com/Followmsnbc Follow MSNBC on Instagram: http://on.msnbc.com/Instamsnbc #msnbc #serenawilliams #tennis