If you can get a Good domain (like from a company that stopped), and it has high PR, then you can start exchanging links with other people, or buying links to retain that PR. If there are no links pointing to the site after the update, then your PR will drop to 0. With a PR4+ you can sell links on your site, and make money. http://www.JustDeleted.com http://www.JustDropped.com Are two good sites. You can find out which sites just dropped, or is going to drop tommorow, which gives you a good chance to research the site's backlink, and PR, before deciding to buy it.
Yeah I was going to say just because it has high PR on the bar does not mean that after a few days it won't go away in reality.
But PR is updated publicly only once about every three months. Means if you can plan it right, you can buy a domain with PR and then have about 3 months to try and retain it.
First thing is check the existing links. Any PR currently showing is from links pointing to the site around Dec. 20/06. Are those links still active? Are they still pointing PR pages to your domain. Lately I've seen some people listing PR domains that have almost no PR links pointing to them so come next update the PR will drop to zero. Yes I know the PR is always updating but its more in the toolbar world we're discussing PR. Than its the tricky part. Do you think those links will still exist in a few weeks/months? You can always start building more links immediately but if you're trying to keep a dropped names PR its so much easier if the links stick around. You just add a few more links and you're good. If you do the research you'll see that certain types of sites seem to keep their backlinks. Problem is the names are usually not generic. So analyse, analyse and than kind of guess. And than development.
He probably meant that adding original content would help in search engines indexing the site more efficiently.. thereby helping to keep the links intact. This in turn means that PR could survive the Google PR update cycle.