CBS News Correspondent Vicki Mabrey reports that the young prince likes Techno music, fast food, and sports. He chooses his own clothes and knows what's hip, though he does admit to liking his prep school uniform at Eton.
And while he may look like his mother, he seems to share more of his father's interests, such as art.
William is the closest thing the royals now have to a superstar. Only he draws the screaming crowds. In a recent trip to Canada, thousands of screaming girls made that clear.
"I remember walking behind them [William and his brother, Harry] with 8,000 screaming teen-age girls," says Charles Rae, a reporter for The Sun, "and Harry realized that when William raised his hand, the girls screamed even more. So William raised his hand to see what happens, and the girls went crazy."
Despite this, William says he doesn't like screaming fans - and the press. Nevertheless, on the occasion of his birthday, agreed to supply written answers to questions the media submitted in advance.
William may not have appeared in public for his birthday, but that didn't matter. You couldn't buy a newspaper in Britain that didn't have William all over it, CBS News Correspondent Mark Phillips reports.
Peter Archer, British court correspondent, speculates that the prince and royal advisers at St. James' Palace may see the questioning - a first for the prince - as a payback to the media who have allowed William the privacy he needs at Eton.
"The palace is now in control," says Ingrid Seward, editor of Majesty Magazine. "They want to remain in control, and thay want to allow us, the media, a certain amount of information but a certain amount only."
The interview also may reflect William's own changing attitude toward public life.
"He doesn't like anything to do with exposure to the media," says royal photographer Arthur Edwards. "He doesn't like anything to do with public life. But he's slowly coming round, and Canada was a kind of turning point."
The public outcry over paparazzi tactics after the death of his mother, Princess Diana, last August was so strong that the British press agreed to police itself and leave William and Harry alone.
"Whether it will last, that's another matter," said Tim Graham, royal photographer, about the kid-glove treatment accorded the two princes.
One newspaper printed a special birthday supplement, and the young prince himself lodged a complaint with the press association. Both sides say the matter has been resolved amicably.
The temptation to become more intrusive may increase as William gets older and takes a romantic interest.
With the age and fustinesof the other royals, even high society royal watchers have had to admit William's unique appeal.
"Charles is 50 this year; his mother is 72, "says Judy Wade, court commentator. "They're all very old and to stay in business, they must appeal to a young audience, and the answer to all that is William."
"No matter how many promises the media make, when William appears with a girlfriend - a gorgeous girlfriend - all bets will be off," said one media watcher.
Prince William didn't reveal anything about his girlfriend in the latest round of questions, so maybe his private life will remain just that - at least, for a while longer.
But public appearances are likely to become more commonplace in the next few months.
His uncle, Earl Spencer, will be featured in a documentary to air in England this week on Diana's early life. Earl Spencer had promised at Diana's funeral to take an interest in William's upbringing, but so far it doesn't seem to have turned out that way.
"The Spencer household want their own way, and the Windsor household want their own way, and William is stuck somewhere in the middle," says Seward.
The memorial museum to Princess Diana opens at the Spencer family estate at the beginning of July. Then, of course, there's the August anniversary of Diana's death. It'll be anything but a carefree summer for young Prince William.