Unsolicited backlinks?

[draggar]

I have a site (PR1) that it seems whenever I post an article I get a "pingback" (it is a wordpress site) to a directory site within a few hours.

I check the URL where the pingback comes from and I see the article posted but when I click on it from there, it takes me back to my site.

Now, I'm not complaining about the free backlinks but I'm wondering do people just surf the web or have a script that looks for newly indexed pages and automatically links them from their sties?

They seem to be from different sites most of the time, the most recent one is bookmarksurl.com

[yandig]

Well there are content sites out there that will also post your article on their site after it's posted to the original article site.
These kind of backlinks can be bad in that they can dilute your Pagerank is you just have one or two backlinks from high-ranking sites. Generally, I don't think it can hurt too much, though.

[harleyx]

A "pingback" is a simple XML script that essentially keeps track of who is linking to your content and from where (by way of a backlink). MovableType, Wordpress, and quite a few other blogging scripts have built it as an automated process within the software.