Until this week, only four acts had ruled the still-young Social 50 chart: Rihanna, the Black Eyed Peas, Lady Gaga and Justin Bieber. But now, we have a new No. 1 artist: Selena Gomez.

And, in an ironic twist, Gomez takes the crown by bumping her boyfriend, Justin Bieber, out of the top slot, and sends him to No. 2.

Gomez skips 5-1 this week thanks to online buzz generated by the release of her third album, "When the Sun Goes Down," on June 28.

Selena Gomez: The Billboard Cover Story

The Social 50 ranks the most active artists on the world's leading social networking sites -- YouTube, Vevo, Facebook, Twitter, MySpace and iLike -- using a formula blending weekly additions of friends/fans/followers along with weekly artist page views and weekly song plays.

What did it take for Gomez to dethrone the Biebs?

First, all of the promotion leading up to her album's release, along with the success of its single "Love You Like a Love Song" helped. The latter has already garnered 10 million views on Vevo. In addition, the July 1 premiere of her romantic comedy "Monte Carlo" didn't hurt either.

Video: Selena Gomez & the Scene's "Love You Like a Love Song"

There's also a candid YouTube video -- uploaded on June 28 -- where Gomez met her longtime crush, "Transformers" star Shia LaBeouf. It has since earned 6.1 million views, respectively (a 146% week-to-week increase). That same day, she also performed another of the new album's hit singles, "Who Says," on "Regis and Kelly." (Also that same day, her "Track-by-Track" video interview with Billboard.com debuted.)

Video: Selena Gomez Meets Shia LaBeouf

These events, among a dozen others, helped Gomez garner 27,000 new YouTube subscribers; 209,000 Facebook fans and 110,000 Twitter followers.

In other moves, Don Omar leaps 26-11. On Vevo, he saw a 68% week-to-week bump in views, most of went to his latest single "Taboo." Since debuting on April 12, it has added an impressive 33 million views. This week, "Taboo" is also sits at No. 1 on the Latin Songs chart.

Across his social networks, Omar gained 154,000 Facebook fans and 106,000 Twitter followers.

After re-entering the tally last week at No. 36, thanks in part to an 820% surge in YouTube plays, the Adam Levine-led Maroon 5 has since climbed nine spots to No. 27. The band uploaded a lyric video for its latest single "Moves Like Jagger" on June 13. The song has since accumulated more than 1.6 million YouTube views. The track -- which debuted at No. 8 on the Billboard Hot 100 last week -- brings together "The Voice" coaches Levine and Christina Aguilera.

Maroon 5 & Christina Aguilera Perform 'Moves Like Jagger' on 'The Voice': Watch

The following week, the pairing also performed the song on the hit NBC TV show. The live debut also found its way to Maroon 5's official YouTube channel (June 28), but contrary to the lyric video, it rests at a mere 171,000 plays.

Back in the top 10, Michael Jackson (7-3), Lady Gaga (2-4), Shakira (4-5), Katy Perry (3-6), Rihanna (6-7), and Beyoncé (15-9) mix up the order, while Eminem holds at No. 8.