I don't really like this term simply because an artist or group is only as overrated as you allow them to be. No one actually forces you to listen to or watch them. But using your perspective of the term, I'd say Rihanna; not because I don't like her, but rather for the comparison of her to well established artists.
I'm torn. I think the person above me is a fake account someone created because nobody sane would ever make such a statement as the first line of that post....and if it's a fake account I should ban it...but then again Rihanna fans aren't necessarily known for their realistic views of the world...so I can't be sure
I think the release of her video for "Disturbia" has drawn more fans. They were probably googling "Queen Rihanna's video for "Disturbia"" and came across ATRL. Quite frankly, there is no other explanation. Well, unless Adrian or Delicious has way too much time on their hands.