Tynt - hijacking your clipboard since I don’t know when
I’m not a huge fan of Tynt.
Here’s the idea in a nutshell. Users visit your site, highlight words with the intention of copying them and pasting them elsewhere. Little do they know that their selection is being transmitted to Tynt’s servers somewhere, and that when you copy that selection (as long as it’s more than one or two words), when you paste, you get a blurb at the end that says “Read more at [title of webpage here] - [link to webpage here]”.
I guess the idea is fine, but I just don’t like it when my computer doesn’t do what I tell it to. That and every time you select text on the page, you can see Firefox thinking and contacting tynt.com about what to do. For a quick example of a page with it enabled, go here