Reality TV turns nobodies into stars. Spoof Internet music videos garner millions of viewers.

Television executives and program makers faced up to an uncomfortable truth Saturday at the Edinburgh International Television Festival: In the age of interactive television and user-generated online content, just about anyone can be a star.

The phenomenon is especially pronounced in Britain, where the fiercely competitive tabloid press requires a constant supply of celebrities — A-list, B-list, C-list and below.

“We don’t really care how they became famous,” said Boyd Hilton, television editor of Heat, the country’s top celebrity magazine.

The rise of the instant star and the increasingly ephemeral nature of celebrity pose a challenge to television’s traditional measures of talent. So it’s no surprise that one of the most popular sessions at the Edinburgh festival was a panel discussion — titled “Don’t You Know Who I am?” — that examined the changing nature of celebrity.