Jenni Rivera Photos: The Latin Diva's Life in Pics
Jenni Rivera attends the 2009 Billboard Latin Music Awards at Bank United Center on April 23, 2009 in Miami Beach, Florida.

Two late artists return to Billboard's Social 50 chart this week, with Jenni Rivera re-entering at No. 3 and John Lennon debuting at No. 40.


The Social 50 chart ranks the most popular artists on YouTube, Vevo, Facebook, Twitter, Soundcloud, Wikipedia, Myspace and Instagram. The chart's methodology blends weekly additions of friends/fans/followers along with artist page views, song plays and reactions.


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News of Rivera's fatal plane crash broke on Dec. 9 -- the final day of the chart's tracking week -- while the 32nd anniversary of Lennon's death occurred on Dec. 8.


Rivera's Wikipedia page logged 275,000 views last week (up 2,978% from just 8,900 the week previous). The increase is expected to carry well into next week, given that only half a day factored into the increase of activity around her name. Her Facebook and Twitter profiles received a boost as well: she added 377,000 fans to her Facebook and 432,000 followers on Twitter.


John Lennon's rise in the tally wasn't nearly as dramatic given that he normally carries a fairly high follower acquisition rate. His overall weekly fan acquisition rate increases by just 6%, with 128,000 new Facebook Fans added. Wikipedia page view traffic increases by 109% during the week as well, a number that will likely drop back down to the normal rate of activity the following week.


JINGLE JAMS: Justin Bieber rises to the No. 1 spot on the Social 50 once again, dethroning Rihanna (1-2) with a 51% increase in weekly Facebook reaction. That translates into the addition of 590,000 new fans on the platform (198% rise over previous week) and 299,000 new followers on Twitter. During the charting week he performed at the Z100 New York's Jingle Ball concert alongside Taylor Swift (who slips 3-5 in the tally), Ne-Yo, the Wanted, Jason Mraz, One Direction (holding at No. 4) and Fun. Ed Sheeran received a boost in the tally as well after the Dec. 7 event after performing with Taylor Swift on her "Red" album duet "Everything Has Changed." Sheeran re-enters the Social 50 at No. 33 following a 160% rise in weekly Facebook reaction leading to 278,000 new fans overall adding to his score.


METALLICA'S SPOTIFY SURGE: While news that the giants of metal obtained the rights to their original master recordings garnered media attention two weeks ago, this past week's big announcement was that Metallica's entire catalog is now available for streaming on Spotify. The band broke the news at a Dec. 6 press conference where Lars Ulrich and seemingly long-time nemesis Napster co-founder Sean Parker appeared on stage and reconciled their differences. While none of the band's tracks entered the On-Demand Songs chart for the week, they did manage to continue their climb on the Social 50, rising 46-39 in the tally with the addition of 139,000 new Facebook fans (2% weekly increase) and 10,000 new followers on Twitter (a 17% weekly increase).


To round out the rest of the top 10 on the Social 50, Bruno Mars continues to climb (8-6) as "Locked Out Of Heaven" hit No. 1 on the Billboard Hot 100 over the week. Nicki Minaj rebounds into the top 10 (14-7) as does Selena Gomez (15-8) while Alicia Keys (6-9) and Katy Perry (9-10) experience declines.