The Billboard Hot 100:
As previously reported , Rihanna returns to the Billboard Hot 100 summit for a ninth total week at No. 1 with "We Found Love," featuring Calvin Harris. That's the longest reign since Ke$ha's "TiK ToK" also led for nine weeks two years ago. Who else clocks in with notable chart news this week?
-- Adele: As her current single "Set Fire to the Rain" roars 8-4 with Greatest Gainer/Airplay honors and former No. 1 "Someone Like You" remains in the top 10 (9-10), "Rolling in the Deep," the first single from her album "21," eases down 30-36 in its 53rd week. As the song earned the title of Billboard's top Hot 100 title of 2011, "Deep" ties Faith Hill's "Breathe" (53 weeks, 2000) for the longest residence on the Hot 100 ever for a No. 1 song of the year.
-- Tyga: The rapper's "Rack City" charges 40-23. As the track surges 35-13 on Hot Digital Songs (113,000 downloads sold, up 20%, according to Nielsen SoundScan), radio support continues to build (21 million, up 26%, according to Nielsen BDS).
-- David Guetta: "Turn Me On," featuring Nicki Minaj, vaults 51-25 as the Hot 100's Greatest Gainer/Digital award winner (96,000 downloads, up 42%). It's one of just eight entries on the 75-position Hot Digital Songs chart to post a gain, as most titles' totals tumble after bustling holiday activity. (Bullets on the tally were awarded primarily to songs registering the smallest decreases).
-- Kelly Clarkson: Following her Jan. 7 performance on NBC'S "Saturday Night Live," "Stronger (What Doesn't Kill You)" improves by 58% to 53,000 in digital sales and re-enters the Hot 100 at No. 58. After notching two weeks on the list as an album cut, the song by the original "American Idol" champion is now being promoted as the second single from her album "Stronger" and airplay for it is already quickly swelling; it appears likely to enter the Mainstream Top 40 chart next week. Related reminder: "Idol" returns to Fox on Jan. 18.
The Billboard 200:
Ringing the bell at No. 1 for an amazing 15th week is Adele's "21,"  which shifted 124,000 last week (down 14%). It's the only set to sell more than 100,000 copies, as Drake's "Take Care" at No. 2 moves 42,000 (down 41%). With the market still adjusting back to normal after the holiday shopping season, the bulk of the chart's titles all see sales declines. So, the criteria for earning bullets had been adjusted so that any album with less than 25% drop in sales garnered a bullet.
Now that we have that housekeeping business out of the way, let's take a gander at some of the tally's movers and shakers this week outside of the top 10:
-- Skrillex: At No. 15 this week is Skrillex's "Bangarang," (19,000; down a moderate 18%) rising four slots from its debut last week (24,000). While there was a chance that the set was going to shift into the top 10 this week -- as we reported last Friday -- the top 10 leap didn't quite happen. However, its physical CD release on Jan. 24 should help keep sales steady as we head towards the Feb. 12 Grammy Awards, where the act is nominated for five trophies.
-- Toby Keith: The "Red Solo Cup" singer's album was offered as AmazonMP3's daily deal on Jan. 5 for $3.99, which prompts its 9% overall gain -- the only increase in the top 50 this week. It rises from No. 32 to No. 14 with 20,000 sold. (In terms of downloads, it's up by a whopping 27%.)
-- Mindless Behavior: The vocal quartet's "#1 Girl" album passes the 200,000 cumulative sales mark this week with another 7,000 sold (down 16%). The album rises 95-70. The album's relatively small erosion could be owed to the buzz generated by the act's performance on "The Ellen DeGeneres Show" on Jan. 4. Meanwhile, the group's latest single, "Girls Talkin Bout," climbs 63-61 on the Hot R&B/Hip-Hop Songs chart. It's the follow-up to the No. 8 hit "Mrs. Right." (Fun chart geek fact: when "Right" hit the top 10, it made Mindless the first non-rap group to enter the top 10 since the Pussycat Dolls' "Don't Cha" hit the region on Aug. 13, 2005. Mindless also returns male R&B groups to the top 10 for the first time since 112's "U Already Know" (April 23, 2005).
-- AWOLNATION: The act's "Megalithic Symphony" album rises to a new peak, jumping from No. 136 to No. 105 (5,000 sold; down 15%). Its most recent single, "Not Your Fault," has perhaps peaked at No. 15 on the Alternative airplay tally -- as it slips two spots to No. 15 this week. Over on the Heatseekers Albums chart, "Megalithic" inches ever closer to graduating from the list as it climbs back to No. 1 (up two slots) for a sixth non-consecutive week at No. 1. (Once a Heatseekers-charting album rises into the top 100 on the Billboard 200 chart, it graduates from the Heatseekers list and is removed from the tally.)
-- Fleetwood Mac: A Jan. 3 repeat of the "Rumours"-focused episode of Fox TV's "Glee" bumps the band's classic set back onto the list at No. 158 with an 83% sales gain. In 2011, the album sold at total of 144,000 copies (thanks in large part to "Glee") -- way more than the 48,000 it tallied in 2010 or 66,000 in 2009.