As part of a large-scale privacy investigation, I have bought more than 100 domain names previously belonging to social welfare and justice institutions in Belgium. What I observed was unsettling.
Search engines such as Google need to rank results in some way, to decide which ones to display on top.
This algorithm changes depending on new developments, both cultural and technical, see Google recently putting results from reddit firsts.
One typical way to do this is checking "how many other websites are pointing at this result", and since traffic is money, people try to game the algorithm by creating fake websites which links to the one they want to push.