Blink-182 debuts at No. 21 on Billboard's Social 50 due to the buzz generated by the release of the video for their latest single "Up All Night." Since debuting on Aug. 25, the video has accumulated 2.2 million YouTube views. The next day, the group challenged fans to upload their favorite screenshots from the video to their Facebook page, tag themselves to the picture, and Like the best ones.

Over 6,000 fans opted to participate in the contest and within a few days Blink-182 grew overwhelmed by the response and decided to name the winner and end the contest.
 
The audio for the single "Up All Night" first appeared on July 14 and has since brought in 2.1 million views. Impressively, the video has already surpassed that mark by nearly 90,000 views.

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In total, the video release helped grow Blink-182's fanbase by 476,000 fans week-to-week. Their latest album "Neighborhood" will hit stores on Sept. 27, 2011.

Billboard's Social 50 chart 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.

With the web buzzing about her "Dream Out Loud" tour, Selena Gomez skips 7-3.
 
While on the road, she has uploaded several video updates to YouTube, helping her pull in an extra bounty of YouTube views.  The first video in the series, which went live on Aug. 1, showed the moments leading up to the first show; it has since brought in 2.8 million views.

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Most recently, a video released on Aug. 31 showed Gomez as she met fans in Philly and Chicago during her signing sessions at K-Mart, where her clothing line is sold. In other web activity, she's collaborating with the Facebook app MyFlipbook to hold a contest where fans can submit photos for a chance to appear in the new lyric video for her latest single "Love You Like A Love Song." Altogether, these events helped Gomez add 204,000 fans and earn 5.3 million plays this week.
 
Tiffany Alvord scores a 32-24 push up the tally thanks to the release of the video for her original song "Unforgettable," which went live on Aug 26. Since then, the heartfelt song has done well, bringing in 308,000 YouTube views. While the video strikes a milestone in Alvord's young career, it also celebrates another one: the passing of 500,000 channel subscribers.
 
Her previous cover video, "How To Love" by Lil Wayne (20-17) came out on Aug. 18 and became quite successful, pulling a cool 754,000 YouTube views. Lately, Alvord has also collaborating with Boyce Avenue, who themselves fell of Social 50 this week. Their cover of "She Will Be Loved" by Maroon 5 has gleaned 2 million views since being uploaded on Sept. 4.
 
With this, she adds 15,400 fans and boasts her views up to 186,000 week-to-week. Through the mid-September, she is on a U.S. tour with fellow YouTube stars Alex Goot and Luke Conard.
 
Unsurprisingly, the Red Hot Chili Peppers continue to clean house, blasting further into the top ten, with a 10-5 surge. Since last week, the video for the single "The Adventures of Rain Dance Maggie" has climbed from 2.2 to 3.4 million YouTube views. On August 31, the group uploaded a series of interviews, featuring thoughts from singer Anthony Kiedis and bassist Flea. Altogether, the videos have accumulated just over 100,000 views-enough to nudge them up the tally. Across all monitored social networks, the group's fan base grew by 152,000 fans.

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As for the rest of the top ten: Justin Bieber (No. 1) holds his respective position. Meanwhile, Rihanna (5-2) and David Guetta (12-6) rise up the tally and Lady Gaga (3-4), Adele (7-6), Michael Jackson (4-8), Shakira (9-2), and Eminem fall down (9-10).