I'd like to take this time to clean up the tags, but before I do so, I'd like to confirm a few things:
1) Are we tagging backgrounds? I like this idea, if we keep the tags general (ie yukkuri_nest_hole indoors simple_background outdoors). Those four tags should be enough.
2) Ratings, almost everything should be safe, but there are a few that might have unsavory implications or mild nudity. I think I'm going to change the ratings on the latter to questionable since this booru is safe-oriented.
3) I don't speak Japanese, but I have noticed that a lot of artists have "aki" at the end of their name. Should this be hyphenated?
4) I have tried to avoid using the pet tag if it's possible that the given yukkuri is not actually a pet. I think that I'll change that. Is that OK with everyone?
5) Emoticons, I like +_+ but I'm not sure if the rest need a tag. I'll tag ^_^ and >_< for now, but leave/delete the rest.
6) Series, if something is definitely a series but I don't know the name, I'll make one up and someone who does recognize the title can fix it.
I think that's it. I'll start fixing the tags soon, but I plan on waiting a bit to give people time to voice objections/give advice.