This doesn't happen every day but now and then I will stumble across someone who has created backlinks - say on a profile page such as the method Angela Edward uses - and I know I can create a link there too. Great one backlink. Sometimes though you get lucky and find someone who does something similar every time they create a backlink such as uses the same username or links in a cluster using the same group of sites. I just came across such a person and can probably replicate a few thousand links. A lot of them I know of already but there are a few beauties in there.