Katie Couric's Notebook: Walkman

When the Sony Walkman was first introduced on this day in 1979, its creators were skeptical that it would generate revenue.

What it did was start a revolution.

For 30 years, everyone from grade schoolers to grandmas have been strutting their stuff on the streets - with a personal soundtrack accompanying their every move.

Since it debuted, Sony has sold 385,000,000 units - but the tune has changed in recent years. The iPod and its signature white earbuds have made the Walkman a bit of a relic like an eight track.

Still, those of us old enough to remember the first time you could jog and listen to your favorite songs - maybe on that mixed tape your boyfriend gave you – well, we won't forget the Walkman.

In fact, since 1986 the word "walkman" has been in the Oxford English Dictionary. For many people it's the Kleenex of personal and portable audio devices.

Then again, I still call CD's - records.

That's a page from my notebook.

I'm Katie Couric, CBS News.