Since I've started studying astrology I've always correlated several things to the planet Neptune. In western astrology, they've always tried to correlate Neptune to a personal level when reading charts; which there is an error in judgment with this philosophy because of the speed in which Neptune moves through the constellations. I've always found that Neptune has always depicted the "generation" or the overall characterized movement of an era.
Examples of this are Neptune in Libra in the 1960s all the way up to 1970. There was a movement during this time known as the "hippie era"; which proposed free love which really characterized the sign of Libra. The era effectively ended when Neptune left the nakshatra of Vishaka. During Neptune's stay in Vishakha, there was much drug use;especially strong psychedelic. Vishakha is usually characterized by extremes; and is usually quite occult; often categorized by lightening.
Then Neptune made its way through the rest of Scorpio; which continued the gradual transformation. If anyone knows the world history of the 1970s, especially in the US, it was a rather eccentric period that involved a lot of sexual experimentation. The music had a much more darker feel to it than the 1960s(which was more free floating). The art in general had a much more darker feel to it.
Continuing Neptune made its way through Sagittarius, and you had a lot of expansion and capitalism. Space exploration, invention of the computer etc. The art was much more toned down and "respectable".
This carried on and evolved more into Neptune in
Capricorn, a period where respectability became the most important thing. People became so concerned with how they looked, what was done wrong, what was done right. We are on the process out of this era, as Neptune now currently resides in the first portion of Aquarius.
The reason I made this post is there is something rather weird that I noticed. And it is not that I buy into the 12-21-2012 stuff, because I've always kind of been on the side that everyone blows things out of proportions etc. Give are take a very small change in the ayanamsa, 12-21-2012 is possibly the day that Neptune enters the nakshatra of Satabhisha. The odds of that happening around that day are somewhat astronomical in proportions because of the rate that Neptune moves. And I still don't think the day is going to be the "end of the world" or anything like that; it's just something to note and to think about.