It’s been a big week for Stefani Germanotta aka Lady Gaga. The pop-singing superstar celebrated her 25th birthday and is in the midst of getting ready to release her third album, Born This Way.

This week, she also made microblogging history as her Twitter follower count ticked past 9 million.

According to figures from social networking sites Twitter and Weibo recorded on April 4, American singer Katy Perry has been attracting lots of new fans too. She has leaped over American actor Ashton Kutcher to become the sixth most popular microblogger on Twitter.

American reality TV star Kim Kardashian may have been criticized for her revealing outfit choice at this week’s Kids' Choice Awards but her fan count has excelled past 7 million.

A constant stream of adoring fans have started following China's top microbloggers this week, but after last week's list of milestone-breaking fan counts, Weibo is relatively event-free.

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 according to Listorious:

  1. Lady Gaga (9,187,534 followers)
  2. Justin Bieber (8,552,854)
  3. Britney Spears (7,326,187)
  4. Barack Obama (7,244,337)
  5. Kim Kardashian (7,005,981)
  6. Katy Perry (6,524,351)
  7. Ashton Kutcher (6,516,578)
  8. Ellen DeGeneres (6,335,582)
  9. Taylor Swift (5,836,596)
  10. Oprah Winfrey (5,499,504)

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

  1. Yao Chen (7,237,054 followers)
  2. Xi?o S (6,290,718)
  3. Zhao Wei (5,889,250)
  4. Cai Kang Yong (5,609,416)
  5. Xie Na (5,131,935)