Given to popular entertainer(s) who have grown up under the close eye of Disney and gained their popularity through the corporation.
Usually, the fans are mostly 10 year old girls who have nothing better to watch or listen to.
The first 'Disneyfed' singers were produced by the Mickey Mouse club, but it now applies more strongly to figures such as Miley Cyrus/Hannah Montana or the Jonas Brothers.
These performers can still have some talent, and they often do, but it seems to be a problem as it ruins their further careers after working with Disney, e.g. Zac Efron
Miley Cyrus is only really popular because of her father. If she hadn't been Disneyfed so much she wouldn't be half as popular as she is now.