If you have getting a link on a PR9 site and you have the option of getting 1 link there or say 10 links there. Does it help any to have more than 1 inbound link put on the pr9 site. Lets just assume there is 0 costs. Is there any benefit to having 10 links to your site there instead of just 1. I assume the 10 links would go on different web pages. But does google count all 10 or will it just say ok this site mentions that site and move on. Or maybe you get diminished returns. So if you had 100 inbound links the 100th link wouldnt be worth anywhere near the 10th inbound link google ran across while ranking you.
I believe that 1 or 20 links only counts as one vote towards your site. thus defeating sitewide linking.
I am a subscriber to the more is better theory, however like Tony Sinclair keeps saying: "Always in Moderation". Means don't overdo it. Try to get one to the root and some more deep links and point one to my sites for the tip
I would recommend that you use a different link for each one you get. If you can get more than one link there then by all means do it, just dont use the same anchor or url. Also try to make the links as relevant as you can to the page the link is on and to the page on your site it is linking to.
AFAIK, PR is passed from individual pages, not the site as whole. So if you have a link on ten pages, that's a better vote than just one. But, as already said, you should be careful that they are relevant. If there is a very good reason for 10 same url links from 10 pages, than that could be ok, too. But it sound dangerous Rainer