As it watches traffic mushroom, video upload site YouTube went offline for about an hour on Wednesday starting at about 10 a.m. PDT.
Company spokeswoman Julie Supan said during a phone interview that she was unaware of any problems with the site. But minutes later, the company posted a note on its front door.
"We are currently rolling out new changes to the site," the note read. "We'll be back as soon as we figure this out."
Supan didn't mention any planned construction or outage to the site during the phone interview.
Teenagers and young adults are flocking to YouTube, one of the Web's fastest-growing sites. With possibly millions watching, young people are dancing in their underwear, lip-syncing to their favorite songs or just ambling around their bedrooms. The more talented or compelling personalities could be harbingers of a new kind of Web celebrity, one that eventually could hold sway with the teen demographic, marketing experts say.