Some of you, and I won't name names, choose to leave meaningless comments with the explicit intention of adding a link to your websites. As comments are moderated on this site, I summarily delete any comments of this nature because they do not contribute in any way to this blog.
That isn't to say that I would not allow a commenter to add a link to his or her website, but the comment would have to be meaningful and perhaps useful to other readers. In fact, the best way to get exposure and attention is to offer to submit a guest post, and I will be happy to add a byline with a link to your blog or website.
As with many things in business, it's all about how you go about doing something.