One common (though misguided) SEO practice of the past was creating backlinks through spammy comments and through “pingbacks”.
Today, this is worse than useless for SEO.
The vast majority of blogs have “no-follow” on links from comments, plus Google can penalise you for this sort of link-building.
Let’s take a closer look, though, at why it’s such a bad idea.
You’re probably already familiar with what comments are: most blogs allow them at the bottom of their posts.
Here’s an example from Bad SEO Practices #1: Buying and Selling Links last week:
Spam comments are ones that have nothing to do with the post (more crafty spammers may repeat words from the post or even an earlier comment). The name given alongside the comment will normally be a keyword phrase, and it links back to the spammer’s site.
Many bloggers these days have Akismet or another anti-spam plugin installed; this catches comments before they ever get onto the blog. Most bloggers will also watch out for and delete any spam comments that accidentally make it through.
Even if a spam comment does get onto a blog, though, it’s very little use to the spammer. A tiny number of people reading the comments might click on the link, but since the link itself is “no-follow”, it won’t help the spammer’s Google ranking in any way.
Spam Trackbacks and Pingbacks
For the purposes of this, we can think of trackbacks and pingbacks as the same thing. (There is a difference, and if you’re keen to dig into this, WPBeginner has a great article on the What, Why and How-To’s of Trackbacks and Pingbacks in WordPress.)
Trackbacks and pingbacks are created when another blog links to one of your posts. They appear in your comments section (sometimes before or after the comments themselves) and look something like this:
In the past, spammers used to use these to their advantage, to create a link from your blog to theirs by first linking to you.
Google has cracked down on this since their Penguin update in 2012, and many spammers (and unethical SEO companies) have found that these links now harm their site.
If you’re getting a lot of trackback/pingback spam and want to stop it, you can switch these off. The WP beginner article linked to above has instructions explaining how.
Bottom line: Commenting on blogs, and linking to other people’s posts, are great ways to build up relationships within your niche. Always think quality not quantity here. If you’re leaving dozens of “Great post!” type comments every day, no-one will benefit.