everyone and their dog 

Basically, this is a saying used to describe something that a hell of a lot of people have.

For example, saying "everyone and their dog has a Ford Mustang" would be appropriate.

Or take the following conversation:

emo kid: "check out my ears, I just got them tapered, I'm so original"

person with an identity: "everyone and their dog has gauged ears in 2005"

everyone and their dog by bryan18 September 5, 2005