What is the Habitable zone all about? I've a question on Habitable zone.

Does Habitable zone represent the region where we humans or the living beings of earth can survive?

Or is it a region where life can exist?

If it is second I want to know what are the parameters that are considered for existing of life.
Nothing that complex. Habitable zone merely defined a circumstellar volume where a planet (if any) can receive an amount of radiative energy to keep H2O in the liquid phase.

Yes, it has been based on the requirements for life from Earth, lacking any wider samples.

I encourage you to play around with interactive illustration of concept (Flash applet).