Two More "What's Up With My Blog" Questions

Recently, I’ve started getting a new trackback every day or two. As I understand it, a trackback is a notification that someone else has posted a link to my site. I believe this all happens automatically if both sites use Wordpress (mine does), but I may be off on that. Each time, I am asked to approve, trash, or spam the trackback.

The first several trackbacks came from sites that looked like they were put together by Talosians—they knew what a website was supposed to be, but they had no guide. I suspected bots or other automated phenomena, and ignored the trackbacks.

But this recent spate purports to be coming from legitimate sites, including Garmin and Carmax. Each notification contains the relevant excerpt, always something like the following.

[…]while the sites we link to below are completely unrelated to ours, we think they are worth a read, so have a look[…]…

When I click the link, I’m taken to a legitimate page on a legitimate site, but no such wording, or links, exist.

Question 1:
What’s going on? Why are (presumed) spambots trying to get me to accept a nonexistent trackback to a legitimate site?

Question 2:
Why do I have to approve a trackback, anyway? (For the purposes of this question, assume we’re talking about a legitimate one.) If you post a link to my blog page on your site, it’s done. The link is there. What’s left for me to approve? What do I get out of approving it? And how can what I do affect anything on your site?

OK, I guess that second one’s a multi-part question. Sorry.

Thank you in advance your help.

(1) (A guess.) Maybe the link was removed, or is hidden, or is on another page on the site?

(2) The trackback might lead to a page that you personally find offensive, or to a product or service that you have nothing to do with. You might not want to provide free advertising on your blog.

So if I “Accept” the trackback, something appears on my site? Screw that. I thought it was just a notification.

That’s the way I understand it. No one has ever linked to my blog, so I’m not totally sure.