I believe this is a growing phenomenon, at least insofar as corporate clients are recognizing there are ways to combat negative press. I have seen a few articles recently popping up on this subject.
A few weeks ago we were approached with an interesting proposition by prospective client. What would it take to get a bit of negative press in a forum, written by a disgruntled, renegade consumer, out of the top 20 google results within 60 days?
Well of course seo is not an exact science, and this "reverse seo" was new to me as i had never been approached with it. But i through a number out there and the client ended up buying 240 hours of time over 60 days to get the job done. A *huge* deal to say the least. It has been interesting watching the progress, and as of today, which is day 33, we have the offending entry down to #19...almost there! Previously they were at position 3.
I did struggle with this at first as I was wondering if it was ethical to do such a thing, to flood the web with content, pr, social media profiles, and the like for the sole purpose of supplanting an undesirable result. But i realized that just as each member of society has the right to their opinion, so does each other member have the right to an opposing opinion, and to promote that opinion to the fullest extent possible.
You will find it labeled as "black hat" or unethical in a number of sites if you do a search, but i believe it is a legitimate concern of business and that reputation management is a valid service to offer.