Domande riguardo a frasi esempio con, spiegazione d'utilizzo di "Bl"s

A: Hmmm... where did you see it? Different groups of people use different acronyms for different things.

My best guess as to the meaning of "BL" is either "Boy's Love (やおい), or perhaps "Black Lies". If you found "BL" posted on the Internet in regards to something Japanese related, there's a really good chance that "BL" is standing for "Boy's Love."

A: Do you mean the genre? In that case, I think that term is pretty understandable to the community of readers/viewers who consume such works. Or “shounen ai.”
Even though BL is technically English, “shounen ai” is an equivalent term in the U.S./outside of Japan.
BUT it really depends on the context, because different subcultures use different terms, including m/m, yaoi (sometimes used to classify works with sexually explicit content), etc.
Hope this helps!