Sub-generations within the Millennials?

Even long generations like Baby Boomers and Generation X tend to have sub-divisions within them. The earlier Boomers were the ones who took all the counter-culture stuff seriously, while those born from about 1958 to 1964 couldn't have cared less then or at any time since. The Gen X-ers born in the later '60s and early '70s didn't spend as much of their young adulthood during the fagged-out period from about 1992 and after, while those born in the mid-late '70s were more exposed to it.

Millennials seem to be another long generation, so there might be noticeable differences between earlier and later born ones. On some level, it's comparing the heights of pygmies, but you know what I mean. In my real-life experience and online, the cut-off for Generation Y feels like 1984 (and starting in '79). Those born in '85 and '86 are almost recognizably human, and after all they do have some memories of the culture before it went down the toilet during the '90s. But if forced to choose, they'd still side with '90s rather than the '80s nostalgia and revival, so I put them with Millennials, whose first clear birth year is 1987.

These sub-generations don't seem to span much more than 5 years, which suggests that the Millennials born since the mid-'90s should be different somehow. Almost all my experience has been with the earlier ones, born in the late '80s and early '90s. Not being a tutor anymore, I don't know how high school kids in 2011 are different from those in 2005.

Anyone reading this have a decent impression? Behavior, culture, beliefs, whatever.

My hunch is that the earlier Millennials won't turn out as dorky as the later ones because as adolescents they got to imprint on a period of exciting culture during the housing bubble euphoria of the mid-2000s. There was a revival of new wave music, colorful clothing, and an overall optimistic spirit. It was brief and highly anomalous for the post-'92 period, but it may have served as a shot in the arm (perhaps too little too late) for Millennials' social and cultural development.

The ones born in the mid-'90s and after didn't experience that period when their social antennae were hyper-sensitive and when they start to pay close attention to cultural trends (i.e. as teenagers).