If you run a blog, you no doubt come across spammy comments with links in them frequently. You may know that this can hurt your page in Google, but sometimes people leave comments with links that are actually relevant to the conversation. Perhaps they want to illustrate a point, or discussed the topic at length in their own blog post that they want to share. Perhaps it’s a relevant YouTube video.

Are you allowing these types of comments in? Are you putting a nofollow on all comment links? Should they really be nofollowed if they are in fact relevant?

Google’s Matt Cutts talks about comments with links in a new Webmaster Help video, but from the perspective of the person leaving the comments. A user submitted the following question:

Google’s Webmaster Guidelines discourage forum signature links but what about links from comments? Is link building by commenting against Google Webmaster Guidelines? What if it’s a topically relevant site and the comment is meaningful?

“I leave topically relevant comments on topically relevant sites all the time,” says Cutts. “So if somebody posts, you know, an SEO conspiracy theory, and I’m like, ‘No, that’s not right,’ I’ll show up, and I’ll leave, you know, a comment that says, ‘Here’s a pointer that shows that that’s not correct,’ or ‘Here’s the official word,’ or something like that. And I’ll just leave a comment with my name, and I’ll often even point to my blog rather than to Google’s webmaster blog or something like that because I’m just representing myself. So lots of people do that all the time, and that’s completely fine.”

“The sorts of things that I would start to worry about is, it’s better, often, to leave your name, so someone knows who they’re dealing with rather than you know, ‘cheap study tutorials’. You know, or ‘fake drivers license,’ or whatever the name of your business is,” he continues. “Often that will get a chillier reception than if you show up with your name.”

“The other thing that I would say is if your primary link-building strategy is to leave comments all over the web to the degree that you’ve got a huge fraction of your link portfolio in comments, and no real people linking to you then at some point, that can be considered a link scheme,” Cutts adds. “At a very high level, we reserve the right to take action on any sort of deceptive or manipulative link schemes that we consider to be distorting our rankings. But if your’e just doing regular organic comments, and you’re not doing it as a, you know, ‘I have to leave this many comments a day every single day because that’s what I’m doing to build links to my site,’ you should be completely fine. It’s not the sort of thing that I would worry about at all.”

I doubt that this video will do much to change people’s commenting habits, and prevent excessive comment spam, but at least it’s out there.

Bloggers are going to have to continue being aggressive with comment moderation and/or use nofollows on comment links if they don’t want spammy links making their pages look bad. Of course, if the spammy comments are there, the page will still look bad to users, and Google doesn’t want that either, regardless of whether or not links are passing PageRank.

At the same time, if you’re leaving a comment with a link, and aren’t trying to influence Google’s rankings, you shouldn’t really care if your link is nofollowed, right?