Yes, although I believe it's weighted by population density inside the triangle (the in-game explanation is that you gain points by influencing minds inside the field, in a global struggle for control of the human race).

Yeah and the longer they stay up, the better as every few hours they calculate the total score which then gets averaged out over the course of a week I think.

I played a few years back, just by bike. But players in cars would always be quick enough to take down what I built.

As a rural player that lives in the city nowadays, I don't even feel remotely interested anymore as you can't impact the scores as much as you can in a rural area.