I did this search to check on longevity in the music business. Google Insights goes back to January 2004, a time at which these artists would have been, presumably, been popular searches, as they are the artists responsible for the best-selling CDs of 2003 (one reason I chose 2003 instead of 2004 is that it's a more interesting list).
To see the stats themselves, the top five selling CDs in the USA in 2003 are:
1. Get Rich or Die Tryin' / 50 Cent 6,535,809 2. Come Away with Me / Norah Jones 5,137,468 3. Meteora / Linkin Park 3,478,361 4. Fallen / Evanescence 3,364,738 5. Speakerboxx-Love / Outkast 3,089,849
Ooh! Courier New! How very sexy... so sexy that I'm not going to correct the errors regarding the name of Outkast's album.
Anyway, so that's our starting point. Looking at this graph, we can see that Norah Jones was never as popular on Google as she was on CD players (logical when you consider that her main demographics include people who probably use the internet less often), Outkast had a surprising lack of steam (in 2003 it was as if they were the 'future of music'), and 50 Cent had an amazing 2005. There is, however, a general downward trend here - indicating that all stars do fade, sooner or later.
A bit of random stats: 50 Cent is most popular in Eritrea, Norah Jones in Madagascar (by far), Linkin Park in Nepal, Evanescence in Bolivia and, unique among the five, Outkast is most popular in the USA. Talk about globalisation. Or rather, talk about the domination of the American music industry worldwide...