Basically, it's an expression used to symbolize jealousy across the neighborhood and the
need to keep up with each other. It's usually just technology, but the subject can be
changed to lawnmowers,
cars, etc.
Sometime in 2001...
Joseph:
Dad! May I have the PS2?
Dad: No, you still have your Nintendo 64, right?
Joseph: It can play DVD's.
Dad: Okay, be prepared, I'll drive you to the Best Buy.
Dad, this time on his mind: I'll have to keep up with the Joneses!