I find it a bit odd that Gruber fails to mention the obvious motivation behind this: to get people to click on the links and increase their traffic. It's not about SEO black magic or increasing their ability to track links, it's including an attribution with copied material in order to increase page views and visibility.

Now, I don't like that they use javascript to break your copy-paste functionality. It's unexpected and unrequested, so we are annoyed and confused by it. I wouldn't use Tynt.

Still, it's worth remembering that citations are a good thing. How many times have we on HN lambasted a site for not including proper attribute to copy and pasted text? How many times have we complained when someone pasted a quote or data in a comment here with no citation?

As unsavory and anti-usability as it is, I can understand the motivations behind Techcrunch and NYT. They're tired of their material being spread around without the courtesy of a backlink, and hope that by making it easier to cite than not to cite, they can encourage links.

In an ideal world, I can imagine that copy-paste would include metadata in some less obtrusive and more user-dictated manner. Tynt isn't doing it right, but attribution and links are a good thing to encourage.