Are these comments? Are they spam? Do I want them? Do I care? What are these things.

[quote]If you’re scanning for a quick answer, they’re both forms of comments, but more of a “remote comment” if you will.[/quote]

Someone wants to comment or link to your site, but instead of writing a comment on your site, they’re linking to your site (via a trackback or pingback) and your site is picking up that mention.

Trackbacks

Over at the WordPress codex, they have this to say about trackbacks, which is actually from SixApart:

[quote]In a nutshell, TrackBack was designed to provide a method of notification between websites: it is a method of person A saying to person B, “This is something you may be interested in.” To do that, person A sends a TrackBack ping to person B.[/quote]

So it is something of a comment, but not as directly inserted onto your website.

Pingbacks

Again over to the WordPress codex for explanation:

[quote]For example, Yvonne writes an interesting article on her Web log. Kathleen reads Yvonne’s article and comments about it, linking back to Yvonne’s original post. Using pingback, Kathleen’s software can automatically notify Yvonne that her post has been linked to, and Yvonne’s software can then include this information on her site.[/quote]

Did you get all that? It’s all very similar to just linking to one another’s sites, but in a somewhat more automated way.

Are they good? Are they bad? Most incoming links to your site are good, but if they’re coming from a spammy source, less so. Also, it’s a way to see who’s linking to you and, possibly, who’s stealing your content.