Bruno Mars’ “Locked Out Of Heaven” tops the Hot 100 for the fourth straight week, while Taylor Swift’s “I Knew You Were Trouble.” jumps from #4 to #2. “Locked Out Of Heaven” is now tied with “Just The Way You Are” and “Grenade” as Mars’ longest-running #1 hit to date. “I Knew You Were Trouble.” surpasses its initial #3 peak and now ranks as one of Swift’s four highest-climbing hits to date.

These songs are in the opposite order on Hot Digital Songs. “I Knew You Were Trouble.” is #1 with sales of 582K copies, which constitutes the fourth highest one-week sales tally in digital history. “Locked Out Of Heaven” is #2 with sales of 497K copies, which is the 10th highest tally in digital history. (Sales traditionally swell in the week after Christmas as fans redeem iTunes gift cards.)

This is the second biggest one-week tally for both Mars and Swift. Mars’ “Grenade” sold more copies (559K) two years ago this week. Swift’s “We Are Never Ever Getting Back Together” sold more (623K) in its first week in August. Mars and Swift are the only artists with two of the all-time top 10 digital tallies.

If you were anywhere near a radio last year, you don’t need me to tell you the titles of the top three hits of 2012: “Somebody That I Used To Know” by Gotye featuring Kimbra, Carly Rae Jepsen’s “Call Me Maybe” and “We Are Young” by fun. featuring Janelle Monae.

There are three main things you should know about them. First, none of the five artists involved had ever cracked Billboard’s Hot 100 before. Second, all three hits are nominated for Grammys as Record and/or Song of the Year, which shows an unusual degree of fan and industry agreement. Third, each of the three songs sold more copies than any song had sold before in a calendar year in digital history.

Taylor Swift this week becomes the first artist since the Beatles to log six or more weeks at #1 with three consecutive studio albums. She achieves the feat with Red, which tops The Billboard 200 for the sixth week. It follows Fearless (11 weeks) and Speak Now (six weeks). The Beatles achieved the feat with seven studio albums in a row from Beatles ’65 in January 1965 to Abbey Road November 1969.

Only two other acts have had such lengthy stays at #1 with three consecutive studio albums. The Kingston Trio spent six or more weeks on top with four straight studio albums in 1959 and 1960. Herb Alpert & the Tijuana Brass did it with three straight studio albums in 1965 and 1966.

Thus, Swift is the first female artist to achieve this feat.

Led Zeppelin was the premier hard rock band in the world in 1978 when the Kennedy Center Honors were first presented. But if someone had told you then that Led Zep would someday be selected to receive the honor, you’d have thought he was out of his mind. That first crop of honorees included such old-guard legends as Fred Astaire, composer Richard Rodgers and conductor Arthur Rubinstein. It took the Kennedy Center’s Board of Trustees nearly 20 years to acknowledge rock, in the person of Bob Dylan. At that rate, it seemed likely that they would never get around to hard rock, metal, rap and other edgier forms of music.

Never say never. On Wednesday (Dec. 26), we’ll see Robert Plant, Jimmy Page and John Paul Jones, the three surviving founding members of Led Zeppelin, become the first hard rock musicians to receive a Kennedy Center Honor. This year’s other honorees are David Letterman, Dustin Hoffman, blues great Buddy Guy and ballerina Natalia Makarova.

Kennedy Center Honors recipients are “recognized for their lifetime contributions to American culture through the performing arts—whether in music, dance, theater, opera, motion pictures, or television,” according to a statement on the site.