Madonna is kind of an annoying activist more than anything else these days, but there was a time when she was cutting edge and to be honest, quite risque. This was particularly true in the 80's when it seemed that everything that she made just blew up straight away.
This was actually during a time period (late 80's) where I liked Madonna's style the least. She was constantly pushing the limits with her look and outfits because that was her thing, but this one, for me, just didn't stick. She was also still attempting to crossover into acting and the accompanying film also called "Who's that Girl" was a box office bomb.
While she certainly was quirky and a lot of her stuff seems strange by today's silly standards, Madonna was a powerhouse back in the 80's and is likely one of the most iconic people to emerge from that entire decade. She would go on to have many other number 1 hits.
Love her or hate her (pretty much everyone loved her in the 80's) there is no denying her star-power. At over 300 million albums, she is by far the highest-selling female artist of all time.