Born on the Fourth of July

"Keep your feet on the ground and keep reaching for the stars."

With those words Casey Kasem will sign off today for one final time as host of one of America's most popular radio countdowns. But it won't be American Top 40, which was born on this historic date in 1970. That show is now in the hands of American Idol host Ryan Seacrest.

Kasem, who has retired and unretired about the same number of times as Brett Favre, has been hosting American Top 20 and American Top 10.

And this weekend is his latest swan song. But will this be Casey's final 10 countdown?

10. Miley Cyrus, The Climb
9. Kelly Clarkson, I Do Not Hook Up
8. Pink, Please Don't Leave Me
7. Shinedown, Second Chance
6. Kate Perry, Waking Up In Vegas
5. Beyonce, Halo
4. Pitbull, I Know You Want Me
3. Lady Gaga, LoveGame
2. 30H!3, Don't Trust Me
1. Black Eyed Peas, Boom Boom Pow

That's your Mainstream Top 10 for the week, and American Top 40 and its offshoots certainly have been mainstream through the years. But the music business these days is incredibly fragmented. Billboard also tracks R&B/Hip-Hop, Rap, Country, Latin, Blues, Christian, International, Dance/Electric, Classical/Jazz, International (including Eurochart and Canadian), Soundtracks, Comedy, and who knows what else. Then there's top ringtones, downloads, DVD and VHS sales, video and game rentals and concert grosses.

(It's worth mentioning that Michael Jackson's "Billie Jean'' is this week's top ringtone.)

I think I'd rather remember Casey in his prime, back when the music seemed a better fit for this format and before listeners began twittering Seacrest to play their favorites. Vintage Casey has been possible since satellite stations began replaying his more popular AT40 programs. There's no chance of hearing Miley Cyrus. On the other hand, there is always the possibility that you might run into "Disco Duck.''

But there are scarier things in the world right now.