Who is a Jew?

This is a vexed question. It was the difference between life and death during the holocaust. It determined where you could live under the Tsarist May Laws and it still does under Israel's delegated land laws. Many people are interested in the Jews as a people so what most people who want to know about a subject nowadays do is look it up on Google. And this is where it all gets unpleasant. The number one slot in the Google results for the word "Jew", today anyway, is a neo-Nazi site so there is a campaign afoot to link to the Wikipedia.org definition of "Jew" because the more links a site gets, the higher up the Google search results it goes. Mind you I'm not sure if agree with the wikipedia definition. It calls us a "nation" at one point. But what is a nation? The people of a country perhaps? When you consider that about two thirds of the world's Jews don't come from Israel and most Jews in Israel don't come from there then what country do Jews come from? I mean we can't be called a nation like, say, the French or the Irish. Also Wikipedia lists lots of different types of Jews: religious, secular, Chasidic, Karaite, etc. but it doesn't seem to have heard of Satmar or Neturei Karta. In fact it doesn't seem to have heard of any anti-Zionist Jews. It's almost as if they have an agenda other than defining who is a Jew. Still rather Wikipedia than the neo-Nazis. But what a distinction.