Not long back Google made it clear that SERP results will decrease for websites that are selling links. In no time some of the A-List blogs were kicked out of the SERP results thus sending a shivering wave around the blogging world. These blogs were quickly restored to their original positions once they had removed the paid backlinks but by now the message was clear – no paid backlinks.
Since then webmasters have come up with different alternatives to sport backlinks on their website that do not look paid to big G even when they are. One such escape route was cash donations for backlinks. Websites openly ask for donations to different charities and in return they leave a link to your website on their websites. Who knows if under the table these charities share a section of the donation with these websites or not but for now this method works. Google cannot ban a website for collecting donation for charities!
PR is very outdated and lately it is causing lot of issues to Google: link sales, PR maniacs and so on.
A sudden removal of PR will cause some panic and issues to many applications and sites that use PR queries for various tasks.
So Google is probably removing PR gradually. They don’t update for a very long period, so webmasters learn how to live without it.

Google is starting to put much weight on outgoing link validation, specially with the Caffeine update.
Broken links seem to be an important factor now, the more broken links, the lower your site rank will be.
This way, they want to force webmasters to periodically check all links and remove or fix those dead.
There are a few problems:
- a large number of websites are no longer maintained, but they still have valuable information and there is no one to remove the dead links
- some broken links are broken only temporary, you could remove them, then when they are up again, it’s much likely you won’t notice to re-add them
- you could write a short post about something and continue with a link for details, so if the link becomes broken and you have to remove it, your post become useless, with a broken link it still could make some sense, people see you write about something which for some reason is not up anymore
- some sites have so many outgoing links, it’s pretty much impossible to make sure all of them are valid