The term Cougar is fairly new to the scene however, many people are continuing to use the term. TV shows have been created, movies and now bands are even naming their albums after the older women word. Not too many people are to sure to where this word originated. There is one rumor it comes from a local pub in Canada, where older women frequent. Some guys noticed an older women perusing a younger man. Her persistence to "hunt" the young man reminded bar-goers of a Cougar.
The word Cougar originally was taken as derogatory but, as time has gone on the term has adopted a few additional words; independent, experienced and driven. The word Cougar is viewed differently between almost all persons, some don't agree with the situation these men and women are putting themselves in, to others it simply older women having fun and being youthful once again.
It doesn't matter if you agree with the term or dislike it, it's here to stay. Not to mention you'll continue to see it more and more, so get ready.