While the concept of "yaoi" and "boy's love" are distinct in Japan (NSFW and SFW respectively), in the West, "yaoi" is the common term utilized, and used to refer to both - as a result, don't use shounen ai / boy's love / boy love as tags; use yaoi is:sfw or yaoi rating:q to search for BL instead, and yaoi rating:e for proper yaoi.
While the most common concept of "boy's love" involves men with bishounen features in Japan (and in turn "yaoi" in the West), on Danbooru, as mentioned, this tag applies to any depiction of male homosexuality, including bara and otoko no ko.
Use the bisexual male tag where appropriate instead of the yaoi tag.
This tag doesn't necessarily apply to objects that characters are holding, like the cover of a manga that someone is holding. Use yaoi (object) in combination with fujoshi, fudanshi, and/or otaku instead.
