Generation Y

Got this from an email forwarded by my brother - makes sense with all the Y's I've seen (mostly gross) as well as belly buttons (Generation O?):

The Silent Generation are people born before 1946.
The Baby Boomers are people born between 1946 and 1959.
Generation X are people born between 1960 and 1989.
Generation Y are people born between 1990 and now.

Why do we call the last one generation Y? I did not know, but a cartoonist explains it eloquently below...Learned something new today.