In the interest of free and open discussion (and because I've been known to make mistakes, which I hope someone will correct), I leave this blog open to comments from anyone, with no registration requirement. To date I've gotten very little comment spam. (If you're not sure what "comment spam" is, it's some self-promoting poster child for rectal problems leaving a comment that has nothing to do with the actual blog entry and everything to do with drawing attention to a website they own.) On the rare occasions when I do get comment spam, Blogger is fairly good about moving it to the spam file on its own.
That raises a point I should make for actual readers (and you both know who you are): if you write a comment and shortly thereafter it seems to have disappeared, don't worry. Blogger has moved it to the spam file for some reason, but I still get an email ping that the comment was posted. I always check comments to be sure they ended up in the right place, and if your comment was mistakenly classified as spam (this has happened at least once and at most twice in the history of the blog), I will restore it to its rightful place in the sunshine.
In the past couple of days, I've gotten the same comment spam message twice. Curiously, Blogger correctly identified it as spam the first time but not the second time. It's a link to "Team PotentiaMED" web site. The information blurb on their site is long on meaningless buzz phrases and a bit short on specifics, but I think they are some sort of consulting operation. I'll let you judge their merits for yourself, if you're curious. Personally, I automatically assume that any business relying on spam to get customers probably lacks solid reasons to patronize them (the sort of reasons that would make for an effective conventional marketing campaign). I also don't trust anyone who spams.
By way of contrast, the proprietors of Online Engineering Degree contacted me by email to ask permission to post a comment pointing to one of their pages, a list of Q&A sites. Instead, I devoted a short post to providing the link, since (a) I thought it might be relevant to readers with an interest in industrial engineering and (b) it was not really relevant as a comment to any particular existing post. A writer from Masters in Engineering wrote to me asking if I would like to mention a page listing forums and boards for engineers. The sites listed were potentially useful to engineers in general but did not seem very useful to IEs, so I declined. I want to give both of them credit for doing things the right way.
Now if I can just find a way to report comment spammers to Blogger ...