Name Voyager is a fun piece of coding genius that allows you to see the popularity over time of different names. Plug in your name, or your grandmother's, and watch the graph show variations as you type. Mouse over to get the rank of a name in a particular decade. Very cool.
Now type in "Britney" and see how Britney Spears was part of a naming explosion in the 1980s, and also part of (the cause of?) a sharp decline in its use in the 2000s.
This is not a hint. We will probably not be naming our child Britney.