We've got a medium-size ecommerce site with a few million pages, and an affiliate for one of our competitors has an ongoing routine I can't quite figure out.
The affiliate buys few .info domains per week, creates gibberish subdomains, and sets up bare-bones pages linking to our site on those subdomains. If you try to visit the domain or subdomain home page, you get a "404 Not Found" message. We find these gibberish subdomains linking to us by checking our latest links with GWT, but by the time we find them the links to our site no longer exist on the pages, and it's simply a list of manufacturer item numbers and short descriptions with the affiliate's links to our competitor. GWT is currently showing about 160 of this affiliate's domains pointing to our site.
How is Google even finding these pages, since there are no home pages or site navigation? Perhaps the affiliate deep-links to them from other sites? And why is the affiliate linking to our site? Is it just a temporary thing until the page is indexed so it appears legit, and then he replaces the links to our site with his affiliate links to our competitor?
If this activity doesn't hurt our standing with Google it's not much of a problem, but post-Penguin we certainly have reason to be paranoid about what could appear to be a sketchy backlink scheme. We're continually adding these domains to our disavow file, but it feels like an endless game of whack-a-mole.