I noticed that sometimes my own spam often outrank my site in search engine. I also noticed that those are unworking spam. Spam that don't give you real links. Why? Well, if they give enough link juices for everyone then they won't rank. Just get rid of them manually and we fix a lot of non live link issue. This is a big deal. If your own spam outrank you, that means your rank drop by 1. 16 such sites and your hard work become meaningless.