Let's remove kaomoji questions from the JL scope.
Why? Kaomoji/emoji alter the nuance of whatever sentence they are attached to, or convey meaning on their own, and this nuance-change or meaning may differ by language.
Especially in the case of kaomoji in Japanese, the vast majority of Japanese kaomoji are not used outside of Japanese (outside of Japanese text) and have a deeper connection to the language.
⊂((・x・))⊃ conveys meaning or nuance to a Japanese internet user which it doesn't to an Anglophone.
Furthermore, the meaning of some kaomoji may not be immediately obvious except to Japanese speakers, or even be the opposite of what you might expect. (
＼(^o^)／ for example).
Should people not be able to ask about a Japanese sentence they didn't understand, just because it's the kaomoji part which is throwing them off? That kaomoji could change the nuance of the sentence for a Japanese speaker.
Or perhaps somebody is chatting in Japanese and their correspondent replies with a single kaomoji which they don't understand. This kaomoji is obviously meant to convey meaning to a Japanese speaker. Can this not be asked about under the scope of Japanese Language?
I would much prefer to have one canonical community wiki which compiles all known kaomoji that such questions can be closed against.
Not only is that impossible simply due to the shear number of different kaomoji, there are also new ones being invented all the time, and new usages being developed. Different kaomoji listing websites have entirely different kaomoji listed under the same headings (sad, happy, thanks, etc).
Regarding the linked question specifically, there's also the fact that it essentially is a translation request, but that's another discussion.
I think this will be the case for most kaomoji questions. But look at the difference between, for example, 'What does
honyaku mean?' and 'What does
The former shows a lack of effort: the answer could be easily found in a J→E dictionary and does not need our expert help (hence being off topic here). On the other hand, the latter likely won't be in J→E dictionaries, and will need someone familiar with Japanese internet trends—or somebody with good enough Japanese to look at Japanese sources—to answer.
So to sum up, I think we should treat kaomoji as 'Japanese language' for the purposes of this site, as much as any other internet slang, for 2 main reasons:
1) Most Japanese kaomoji are only used in Japanese contexts, convey certain (sometimes non-obvious) meanings to Japanese speakers, and can entirely change the nuance of Japanese sentences. This makes them a part of the Japanese language.
2) They make for non trivial questions which require expert help.
I can ask about
wwwwwwwww, I can ask about
(ry, I can ask about
wktk, why not about
ps. Oxford Dictionary's word of the year this year is an emoji :P