What is this method called / bought?

Hi all.

I came across a competitors websites backlinks, which has a very specific pattern.
Obviously it's a SEO-product he has bought from somewhere - and I don't know if it's a time-limited product.

Method-description:
His backlinks are only part of a footer on many many sites.
Someone has to own a lot of sites with different content and sell 5-10 links in the footer.
It's a sudden increase in backlinks, which is why I think he has bought a service.

What is this kind of method called? Where you can buy many unique footer-links from a ton of websites?

This is not blog-comment spam, and it seems to work very good.


Thanks for the help.

I know this works great(I read in a WSO), not many seo service providers provide this kind of service.
Some one on DP has a thread selling this kind of service but I do not have the url. Its been 2 months or so, I have seen it by chance.