I like comments that really address the content that I have written, no matter if they agree or disagree with me.
But I am getting a lot of spam these days and comments that advertise pharmaceutical products, credits, dating sites or other non-related issues are spam, when applied to this site, unless we discuss the IT of their web shops, and I delete them. Generally I will delete comments that do not contain content referring to the article, but only consist of links. I like languages and I speak German, English, Swedish, Norwegian, Spanish, Russian and French, but I will usually delete comments in languages other than the article, if their text is not obviously an interesting reference to the article. Even comments like „great blog“ with no content, however nice they are, do not create any value for the readers and will not be released.