I cannot believe it but there are companies out there that will, for a fee, sabotage the search engine ranking of your competitors website. They achieve this through various methods. This is an email sent totally unsolicited to 100 prospective clients by a company specialising in recovering Google rankings for those affected:
The worrying results were that 61 out of 100 companies replied, an extremely high reply rate for such a spam like email. Of those only 2 rejected the offer outright with some choice words, well deserved, 11 politely declined the offer, 19 wanted some more information and horrifyingly 29 accepted the offer immediately and asked for payment details.
Just goes to show how on the ball you have to be in thsi day and age.