I think you are on to something interesting. In the three years I have been here I have watched several new waves of immigration. Initially it was hackers and math geeks giving way to fiscally political libertarians. More recently, serious investors have shown up. Using BTC as a financial instrument. Currently I see a lot of more mainstream Internet users arriving.
Each group has contributed something to the bitcoin culture that has evolved. I can't wait to see who is coming next.
I primarily got interested in bitcoin because people I knew were into it, but as a computer science geek, I also thought it was pretty technically interesting. I think this was probably during the second wave that you mentioned.
I'm curious what the future will bring for bitcoin as well! I get the impression that there may be some mixed feelings about more mainstream internet users getting involved with bitcoin.
Could you elaborate a little on what you think the different waves have contributed to bitcoin culture? Also, do you feel like people from the different waves interact together well?
(Feel free to PM me a response if you'd prefer to talk in private. And of course, please don't feel obligated to respond if you don't want to answer my questions!)