The point of it being the north star is that if you were to extend the planet's rotational axis to the north it points close to Polaris (actually it points about one apparent moon diameter away from Polaris along a line towards Kochab).

On a geologic time scale, this is very temporary. Our planet is precessing (wobbling like a slowing top), so where the axis points is changing. The axis once pointed at Thuban, some time in the distant future it will point at Vega.

Why would I know this? I use something called a "tracker" that lets me take long exposures of the night sky. The tracker rotates at the same speed as our planet, but the other way; so long as its axis is lined up exactly with the planet's axis, I get no star tracks/trails even over a couple of minutes. See: http://arksky.org/Kochab.htm

In the southern hemisphere, the axis, if you were to extend it, points at pretty much nothing, meaning night sky photographers have to use a guide scope which they have to put an offset into.