What's up with all the celebrity posers?

there's selena gomez,miley cyrus,paris hilton,zac efron,robert pattinson,nichole ritchie,Olson(however you spell it) twins,rosie o'donnel (again don't know how to spell it) and the jonas brothers and britnet spears. anymore to add to the list? there has been so many posers. any ideas why?