To be very blunt about it, Puppy Love can also be referred to as "false love". Puppy love usually happens to younger couples that are inexperienced and/or very naive, although it has been known to happen to mature couples as well.

A relationship based on puppy love always involves lots of cute pet names for one another as well as an extreme need to make the relationship general knowledge; this is often achieved by, although not limited to, sitting on each others' laps and kissing in the public eye.

It is called puppy love because the feelings associated with it are similar to those you would have for a puppy dog. Soon enough, the novelty wears off.