This is a good an informed answer, though he just asked if he could link a website which is entirely allowed. However referral links are not, malicious links are not and advertising for a website is not either. For example using a site/link as a means to communicate information (or as a source) or to emphasize your point made in a post is entirely fine as is posting youtube video links (though you would be better off embedding ) in the proper sections is also perfectly fine.
What would you be linking and why if i may ask, that would give us a much better idea of whether its within the rules or not. Basically most links are allowed as long as its not advertising as jacks post says.