The latest one spotted - "EMBARRASSING: Daddy walks in on daughter!!!" - falls into the second kind, as users are tricked into clicking on a link that takes them to a video seemingly located on YouTube, and which asks them to complete a CAPTCHA in order to access the video:
But the security verification is fake, and it's actually not a CAPTCHA window at all.
"Pressing the ‘submit’ button executes code that posts the malicious video link to all of your friends’ walls," explains BarracudaLabs' researcher. And then, of course, you are offered a few surveys to complete before being able to see the video.