I originally ran this poll a little over 2 years ago (http://news.ycombinator.com/item?id=688053), so I thought it might be interesting to run it again...
Here's how this works: Go back along your family tree until you reach the first immigrant. That is, the first person who eventually settled in a country other than the one they were born in, regardless of country (i.e. this is not intended to be US-immigrant-centric).
Choose only the one answer which corresponds to the most recent immigration. So, for example, if your father is the 3rd generation since immigration but your mother is, herself, an immigrant you would choose "1 generation". The hypothesis we're testing is that the sort of entrepreneurial, adventure-seeking personality that is overrepresented on HN correlates with a willingness to pick up and leave your comfort zone completely.
I'm not aware of any immigrants in my family tree, but I'm only aware of my ancestry two generations back, so I can't answer the poll accurately without additional research. It isn't really worth my time to do that, so I'm not going to answer the poll.
Assuming I'm not a rare exception, the way your poll is worded will therefore be biased toward recent immigrants and people who know a lot about their family tree. Without knowing how much this bias is, there's not a whole lot you can conclude from the results.
You may want to setup an additional poll, such as:
* I am an immigrant
* At least one of my parents was an immigrant
* At least one of my grandparents was an immigrant
My guess is that more people could answer that poll than your current one, and you'd therefore get less bias.