I am doing some SEo on my site and I'm wondering about link backs.
if I link to a site that links to me, do I need to link to the exact page the links to me or can I link to their core domain? So it http://www.fred.com/webpage.html
links to my site do I have to link to the webpage.html page or just http://www.fred.com?
Also I heard there were more than one type of link back, what's that all about?