Referrer Spam. This is one of the main reasons, apart from writer's block, why I sometimes set my blog to Private. While I am okay with the increasing number of page views from visitors, I am highly annoyed by referrer spam. What's worse, some of these links are porn sites!
Normally I would ignore it, but there are times I would investigate the origins of the said traffic, which would show rather alarming results.
Recently, I discovered unusual traffic and also discovered a web link where the traffic originated from. So, I made a search on Google Search and found out that it was a pornographic website, much to my surprise.
I looked up on Google Search again about this, and found out what was called a 'Ghost Referrer Spam' (click here). Although the article is describing Google Analytics which I didn't use, it was a rather surprising discovery for me.
As I didn't use Google Analytics, the best solution for me right now is to ignore it.