I have a main site which is a PR5. I also have a domain that has managed to get a PR4, although it has next to nothing in terms of content. Would the PR5 site gain anything if I redirected the PR4 site to it? I'm thinking the PR4 site has some value and don't want to just leave it sitting there... Thanks. Chris
Yes, if you do a 301 redirect, whatever weight/rank/karma/chi the PR4 pages had will be retained at the new location.
So, in practice, a PR 5 site that receives a 301 Redirect from a PR4 site... will receive good will/karma/ etc from the PR4 site. I assume this is permanent then...once it's set up as a 301, it's a done deal. -Chris