Interesting content in the link from TWT above.
It's an apparent modification to calm down a bit of a war that's developed. In recent months I've been getting regular requests from some pretty big companies to remove links on PPRuNe to their sites. They seem to be coming under pressure from google to request their removal.
We have the policy that if links are from long term ppruners offered to assist others on the site then that is absolutely fine by us. If google have a problem then they can write to PPRuNe. So it looks like the modification to the software is designed to help sites maintain a similar stance more easily.
Rob