FYI... actually it was clickbait. I think you're smart enough to understand that in this context, I'm describing the "mystery link" with no context, not whatever awaits at the other side. In the end, it's something that provides zero information and which "baits" them into clicking out of curiosity, rather than providing any relevant or contextual info.
Clickbait like that is designed to create a "curiosity gap" between what a reader knows (ie: that requires adult verification AND that it's only viewable on Youtube) and what they want to know, often using sensationalism or emotional triggers (like the vulgar headline).
The element of mystery in the blackout thumbnail is the equivalent of the classic "You Won't Believe What Happened Next" which the most iconic clickbait trope, teasing a shocking outcome without revealing any details.
And then there's the classic "What Happens Next Will Make You Cry" which leverages high-arousal emotions like sadness or inspiration to force a click.
"The Truth About [Topic] They Don't Want You To Know" or "We Were Right All Along" taps into paranoia or the desire for "insider" information. (OMG... the hippies were right... but we don't KNOW what this link is talking about... plus it requires ADULT verification... I simply MUST click to find out what I'm missing!'')
Please. It's clickbait. I can spot clickbait a mile away, and this blacked-out, adult-verification required, login at youtube required, mystery content link was definitely clickbait.