The dynamics of the Overbet

Ok... Hope ya'll dont get sick of my general posts instead of specific hands...

I have seen more and more people using the "overbet" lately. What is the point in using it? When do you use it? Why do you use it? It seems like a waste of money to me because if I see someone continually using the overbet as a bluffing technique (which I am seeing more and more of) then I am going to use it against them whether I have a hand or not... Thoughts?