My understanding was that these programs don't rely on YouTube's API, but rather they are loading the page and scraping it for the relevant video files, comments, and other data. So it's a little harder to kill them than just shutting down API access. That said, with all the new web DRM crap getting pushed by Google and others, I can't imagine it will be long before they can detect that you aren't viewing the page the way they want you to view the page, and then block access in some other form.
My understanding was that these programs don't rely on YouTube's API, but rather they are loading the page and scraping it for the relevant video files, comments, and other data. So it's a little harder to kill them than just shutting down API access. That said, with all the new web DRM crap getting pushed by Google and others, I can't imagine it will be long before they can detect that you aren't viewing the page the way they want you to view the page, and then block access in some other form.