The Black Eyed Peas' 2009 smash "I Gotta Feeling" this week becomes the first song in digital history to top the 8 million sales mark in U.S. sales. To find the last song that has sold 8 million or more copies in the U.S. you have to go back to the pre-digital era for Elton John's "Candle In The Wind 1997," which he recorded in the wake of Princess Diana's shocking death on Aug. 31, 1997. The song, which was double-listed with "Something About The Way You Look Tonight," has sold 8,839,000 physical singles, according to Nielsen SoundScan.

Both of these smashes topped the Hot 100 for 14 weeks. (They are two of only seven songs to hang on to the top spot that long since 1955.) Both artists won "performance Grammys" for these songs. Elton won for Best Male Pop Vocal Performance. The Peas won for Best Pop Performance by a Duo or Group With Vocals.

Justin Bieber's new album Believe is expected to sell in the 410K-440K range this week, which would be the year's heftiest first-week total by any album. It would be the strongest first-week tally since fellow Canadian artist Drake opened with sales of 631K copies of Take Care in November. This week's Hot 100 provides two indications of Bieber's strength. "Boyfriend" logs its 12th straight week in the top 10. That's twice as many weeks in the top 10 as Bieber's two previous top 10 hits combined. "Baby" (featuring Ludacris) spent five weeks in the top 10 in 2010. "Never Say Never" (Featuring Jaden Smith) spent one week in the top 10 in 2011.

Also, this is the third straight week that Bieber has had the top new entry on the Hot 100 with a "preview track" from the album. "As Long As You Love Me" (featuring Big Sean), debuts at #21 (Digital sales rank: #5, 168K). "All Around The World" (featuring Ludacris) bowed at #22 last week. "Die In Your Arms" opened at #17 two weeks ago.

"Girl groups" have been with us since the 1930s, when the Boswell Sisters and the Andrews Sisters stormed the charts. "Girl groups" with soul started to come on strong in the first half of the 1960s, with the success of the Shirelles (shown here), the Marvelettes, Patti LaBelle and Her Blue Belles, the Crystals, the Chiffons, Martha & the Vandellas and, most spectacularly, the Supremes.

"Girl groups" (the term is dated, but let's just go with it, OK?) have been training ground for such top stars as Diana Ross, Patti LaBelle and Beyonce.

Three leading soul girl groups are sister acts: the Pointer Sisters, The Emotions and Sister Sledge. Two others, Xscape and 702, each included a pair of sisters.

Carly Rae Jepsen's "Call Me Maybe" jumps from #2 to #1 on the Hot 100, displacing the biggest hit so far this year, "Somebody That I Used To Know" by Gotye featuring Kimbra. That smash dips to #2, ending an eight-week run at #1. Jepsen is the first female artist to reach #1 with her first Hot 100 hit (as a lead artist) since Ke$ha scored with "TiK ToK" in January 2010.

"Call Me Maybe" tops the 3 million mark in U.S. sales this week. This week, it becomes the best-selling hit by a lead female solo artist so far this year. It swipes the title from Kelly Clarkson's "Stronger (What Doesn't Kill You)."