On several of my websites, I noticed a significant number of inbound links coming from irrelevant websites.
For example, one of my site is about travel and one of site that links to it is about male-enhancing pills. The only reason I know of this site is that it appears in my server logs as referrer a certain small percentage of the time. Invariably this site and others that do the same seem to have a bunch (roughly 10-30) of irrelevant links scattered on their pages and some of them happen to point to my site. Now since the links go from their site to mine, it is certainly not about luring traffic towards them, so why would they do that?
More importantly, does this have a negative impact on my site's search-engine and and Google ranking? If so, what can I do about it since I have no affiliation or contact with the offending websites?