Thanks to the release of its new single "I Will Wait," Mumford & Sons  make a long-delayed debut on Billboard's Social 50 chart, arriving at a lofty No. 13. The chart premiered in December 2010, but the band never generated enough weekly social buzz to make the list until this week.
The Social 50 chart ranks the most popular artists on YouTube, Vevo, Facebook, Twitter and MySpace, using a formula that blends weekly additions of friends/fans/followers along with weekly artist page views and weekly song plays.
"I Will Wait" -- the first single from its upcoming album "Babel" (due Sept. 25) -- was released on Aug. 7, midway through the tracking week. It helped contribute 2 million total weekly plays to Mumford and Sons' YouTube channel, nearly a 600% increase over the previous week. "I Will Wait" also debuts on the Billboard Hot 100 at No. 23 this week -- a career-high for the band.
"Babel" is Mumford and Sons' second official studio album and follows "Sigh No More," which peaked at No. 2 on the Billboard 200. That set has sold 2.4 million in the U.S. according to Nielsen SoundScan.
The band added 25,000 new Facebook fans last week, a 44% increase in weekly acquisition, bringing its total of likes to 3.07 million. A 76% jump in Twitter followers was concurrent with the release of the single as well.
Elsewhere on the Social 50, One Direction  bounces 16-5 after scoring over 185,000 new fans on Facebook, contributing to a 9% gain over the previous week. A Facebook competition involving the group's single "One Thing" helped stir the increase. Fans were encouraged to upload their own cover of the song, which was then remixed into the original tune's video via a custom-build Facebook application.
The app (Sing "One Thing"), developed by Audish, helped generate a social campaign that received thousands of submissions and helped boost fan participation. It also didn't hurt that during the week, One Direction was prepping to play on the world's stage at the closing ceremony of the Olympic Games in London (Aug. 12).
Beyonce made strides as well, rising 33-22 as her "I Was Here" campaign for World Humanitarian Day began just before the charting week, swinging a large amount of online attention her way. Via updates to her Tumblr blog, she encouraged fans to pledge online support and share their support by spreading the message on Twitter and Facebook. The campaign contributed to a 25% leap in weekly overall fan acquisition for Beyonce.
Skrillex  leapt in the tally (31-17) with a 198,000 gain in Facebook fans contributing to a 35% increase in overall fan base. A healthy discussion around the video "Cat Rats" occurred on his Facebook page, where Skrillex is known to frequent and talk with fans. That back-and-forth contributed to an overall Spike in engagement.
Down at No. 39, another YouTube cover artists enters the Social 50 fold. 17-year old singer/songwriter Megan Nicole climbs her way onto the chart. She's garnered more than a million subscribers to her YouTube channel and owns 724,000 fans on Facebook.
As for the top 10: Rihanna  returns to No. 1 (3-1) as Justin Bieber  gets bumped down to No. 2. Katy Perry  (4-3), Adele  (5-4) and Taylor Swift  (7-6) slide up in the rankings. Shakira  lifts (12-7), Nicki Minaj  tumbles (6-9) and Lady Gaga  holds fast at No. 8. Meanwhile, Pitbull  anchors the end of the tally, dropping a slot to No. 10.
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