A couple of weeks ago Justin Bieber become the most followed (i.e., most popular) profile on the entire Twitter network, usurping long-term numero uno Lady Gaga.

Since then, Bieber hasn’t looked back, extending his lead over Gaga to a couple hundred thousand followers. Indeed, Gaga faces increasing pressure for the #2 spot on Twitter from Katy Perry – as we’ve seen time and again on Twitter, nobody is safe in the top spot, no matter how popular they seem at the time.

Here’s an updated look at Twitter’s 10 most-popular users.

1. Justin Bieber (@justinbieber, 34,092,083 followers)
2. Lady Gaga (@ladygaga, 33,883,513)
3. Katy Perry (@katyperry, 32,041,889)
4. Rihanna (@rihanna, 28,191,854)
5. Barack Obama (@barackobama, 26,933,033)
6. Taylor Swift (@taylorswift13, 23,725,807)
7. Britney Spears (@britneyspears, 23,711,508)
8. Shakira (@shakira, 19,703,172)
9. Kim Kardashian (@kimkardashian, 17,337,110)
10. Ellen Degeneres (@TheEllenShow, 16,607,717)

Meanwhile, YouTube continues to reign supreme as the top brand on Twitter, ahead of Twitter themselves and Instagram. Indeed, YouTube’s following is strong enough to put it inside Twitter’s overall top ten, in the eighth spot.

As you might expect, six of the top seven brands on Twitter are social channels or platforms.

1. YouTube (@YouTube, 22,972,851 followers)
2. Twitter (@twitter, 16,140,091)
3. Instagram (@instagram, 15,262,242)
4. Twitter en español (@twitter_es, 11,191,852)
5. CNN Breaking News (@cnnbrk, 10,299,357)
6. UberSocial (@ubersocial, 9,384,826)
7. TwitPic (@twitpic, 8,675,911)
8. FC Barcelona (@FCBarcelona, 8,078,209)
9. The New York Times (@nytimes, 7,434,681)
10. CNN (@cnn, 7,335,027)

(Source: Twitter Counter.)