On the world's largest encyclopedia that anyone can edit, and where its content has a powerful search engine presence, spam is an inevitable and ongoing problem. Link spam in particular can easily go under the radar. Most search engines such as Google base their results not only on the search terms but also by how many other sites link back to a certain site, and how many other sites link to those sites, etc. Wikipedia is one of the top 10 websites in the world, so obviously it is a prime target for link spamming. Fortunately admins have numerous tools to fight any form of spam.