Advertising spam

I'm getting a bit of junk coming through my comments box lately. Something to do, perhaps, with the mention of cancer sending out a kind of alert to all the many websites selling pain relief or alternative cures....  I'm not ready to change my policy on comments, yet, but if you see traces of comments that have deleted by the blog administrator, it's because they are of the generic "I like this post and thought I'd leave a comment but don't know what to say" variety, usually featuring a link to a website that says if you take a special vitamin supplement you won't get cancer. Nothing more sinister than that; but nothing conducive to the friendly interchange of ideas and thoughts amongst human beings, either.