If you're a celebrity on Twitter, it's easy to judge how famous you are: by the number of followers you have.
Serena Williams has nothing to fear in the popularity department. The 13-time Grand Slam champion has more than 2.7 million people hanging on her every tweet. And she feeds her fans food for thought on a daily basis.
No other WTA Tour players come close to cornering that kind of Twitter audience. It's proof that Williams' fame has transcended the sport of tennis.
The sixth-seeded Williams, who beat Barbora Zahlavova Strycova of the Czech Republic, 6-2, 6-4 in the first round at Wimbledon on Tuesday, offers a couple of takes on why she's a favorite.
"I think just being involved in a sport that's traditionally white and being a black girl and coming out and doing so awesome in general is gonna open eyes of watchers that don't normally watch tennis, or have never even thought to watch tennis," said Williams, 30, who won her first Grand Slam title at the U.S. Open at age 17.
"I also think that I have a pretty outgoing personality," she added. "Normally I'm pretty upbeat and funny. I think I'm really an outgoing individual, and I'm not afraid to wear my emotions on my sleeve or speak my mind on a lot of different things, or just be myself."
One reason Williams' fan base is so extensive is her interests are wide and varied. On Twitter, she posts about many different things. Williams recently introduced her stuffed animal monkey, Max, as her son -- complete with picture. She also cheered for the Miami Heat, followed Euro 2012 soccer, offered up her dinner menu and shared her musical taste.
Of course, there's a mention of her tennis career now and again, too.
Williams has performed at an extraordinary level in majors. Beyond her 13 titles, she has recorded a non-calendar Grand Slam -- winning all four majors consecutively, from the 2002 French Open to the 2003 Australian Open. She is one of only five women to win four majors in a row, and the achievement was immediately dubbed the "Serena Slam."
She's won four of her 13 Grand Slam trophies without dropping a set: 2002 and 2010 at Wimbledon and 2002 and 2008 at the U.S. Open. She's the only player to win three Grand Slam titles after saving match point: 2003 and 2005 at the Australian Open and 2009 at Wimbledon.
This is her 48th career Grand Slam appearance, and the recent French Open marked the only time she has lost in the first round of a major. Williams said she would learn from the early exit in Paris and reflected on it after her victory Tuesday.
"You got to keep going," she said. "I was playing excellent before Paris. I hadn't felt that good in a long time going into a Grand Slam. I was really disappointed. But, you know, as Kelly Clarkson says, 'What doesn't kill you makes you stronger.'"
Williams, who had a life-threatening embolism in her lung last year, said she's usually a "naturally negative" person. But she's pushing herself to be more positive. And one important vehicle in reaching that goal is taking inspiration from her sister, Venus, who is dealing with the autoimmune disease Sjogren's syndrome.
"She's the ultimate," Serena said of Venus. "I don't even know how she can do what she does and still run her business and still play, and play pretty darn good tennis and still be so positive. Whatever I've learned, for the most part, is [that] whatever I'm going through, I can learn from her and always to stay positive and stay upbeat."
While there's no denying Serena would be thrilled to take home a 14th Grand Slam trophy -- and 42nd career title -- at Wimbledon, she also has other things to think about heading into the Olympics in London.
The newest addition to the Olympic tennis lineup is mixed doubles, and everybody is campaigning to play with Serena. Andy Roddick asked first and is a close friend from childhood. He's already threatened to take away a visitation privilege if she doesn't team up with him. Both Bryan brothers and John Isner have also thrown their hats into the ring.
"I love going to Austin," Serena said. "I have so much fun with Andy and [his wife, Brooklyn Decker]. Oh, my gosh. We have a blast. So that's a tough one.
"Honestly, for me, I have to talk to the captain, even both captains, the male and female. We should just see medal-wise who it would be best to play with. Honestly, I wouldn't leave it in my hands because I would make an emotional decision as opposed to a good decision."
For the immediate future -- as in the next two weeks -- it's all about Wimbledon and Serena's penchant for competing, something she's learned to appreciate even more since her health problems last year.
"You know, for that moment in time it's all about you and your opponent," she said of being on a court playing. "For me, I love that feeling. I don't quite know why, but I really do. It's interesting to go out there and just do your best -- and for me to do what I do best, which is play tennis."