I have to admit I am amazed by this technique for spamming that I just discovered. All of the referring sites in my blog's log are fakes. One is a hardcore "amateur" pr0n site, another sells a cure for shyness (natural, I am sure), a third offers information on online degrees. None of these have links to my blog and obviously never did.
This means that there are enough bloggers who check their logs for signs that they are gaining in notoriety (and eagerly visits referring URLs) to make it worth writing a bot to troll the Interwebs while sending false referrer info.
I should do this too. Cheaper than GoogleAds.