In reply to jjsrb.

Rhythm Nation didn't sell 20 million WW or 10 million in the US, you liar. It sold 14 million WW and like 6 million US. And The Immaculate Collection (1990) sold 30 million WW and is RIAA certified DIAMOND - something that Janet NEVER achieved and never will. Fun fact, Madonna has TWO diamond albums and a third nearing it. Janet has none. Miss me on the conjecture.

MADONNA (1983) sold more than JANET JACKSON (1982)
LIKE A VIRGIN (1984) sold more than DREAM STREET (1984)
TRUE BLUE (1986) sold more than CONTROL (1986)
LIKE A PRAYER (1989) sold less than RHYTHM NATION (1989)
**THE IMMACULATE COLLECTION (1990) sold more than RHYTHM NATION (1989) and JANET (1993)
EROTICA sold less JANET (1993)
BEDTIME STORIES (1994) sold less than JANET (1993)
SOMETHING TO REMEMBER (1995) sold more than DESIGN OF A DECADE (1995)
RAY OF LIGHT (1998) sold more than THE VELVET ROPE (1997)
MUSIC (2000) sold more than ALL FOR YOU (2001)
AMERICAN LIFE (2003) sold more than DAMITA JO (2004)
CONFESSIONS ON A DANCEFLOOR (2005) sold more than 20 YO (2006)
HARD CANDY (2008) sold more than DISCIPLINE (2008)

So there! Janet has only 2 albums that roughly outsold Madonna's from about the same time...but then TIC came in and outsold the two albums of Janet's that were outsold other Madonna albums from that period. Madonna has generally ALWAYS outsold Janet. She was ALWAYS the more successful of the two. Much more, actually. That's why both Billboard and Guiness cite Madonna...NOT JANET...as "the most successful female recording artist of all time." Again, Madonna NOT Janet.