Lady Gaga has reached the elusive milestone of 10 million fans.

"10MillionMonsters! I'm speechless, we did it! Its an illness how I love you. Leaving London smiling," tweeted Lady Gaga on May 15, highlighting the achievement.

This is not the first online distinction for the star: in July 2010 Lady Gaga became the first living person to achieve over ten million Facebook "likes" and in October 2010 she accumulated over one billion aggregated views on YouTube.

Barack Obama also had a big week on Twitter, surpassing the 8 million followers mark and leaping ahead of Britney Spears into third place on Twitter's list of most followed microbloggers.

Chinese actress Xie Na edged her way in front of American talk show host Oprah Winfrey in terms of followers this week, making her the 15th most popular microblogger overall.

In September 2010, Twitter had 175 million registered users, while Sina reports that Weibo had more than 80 million registered users in January 2011.

Most popular people on Twitter:

  1. Lady Gaga (10,048,506 followers)
  2. Justin Bieber (9,665,899)
  3. Barack Obama (8,020,131)
  4. Britney Spears (7,845,566)
  5. Kim Kardashian (7,491,647)
  6. Katy Perry (7,306,333)
  7. Ashton Kutcher (6,744,177)
  8. Ellen DeGeneres (6,650,355)
  9. Taylor Swift (6,379,695)
  10. Oprah Winfrey (5,856,790)

Most popular people on Sina's microblog (Weibo):

  1. Yao Chen (8,139,744 followers)
  2. Dee Hsu (7,257,134)
  3. Kevin Tsai (6,613,948)
  4. Zhao Wei (6,447,126)
  5. Jung Kyung Ho (5,964,806)
  6. Xie Na (5,881,196)