I grow weary of these shortcut aliases because we're inevitably going to hit a snag when some popular IP that shares the same initials comes along. Not to mention these shortcuts don't help anyone except the one person suggesting them.
I think having a number of shortcuts to help only one regular tagger is a good idea, if making them is not a particularly troublesome task for jhx. If you don't use them, (because you prefer the auto-completion and whatnot) you can just ignore them.
The "when some popular IP" reasoning is poor. All words, abbreviations and sequences of characters have potential to become names of famous IPs. Maybe some day an awesome manga called "Breasts" comes out, but I woulnd't want to preemptively change/delete/rename breasts based on that. If/when the time comes, Danbooru will know what to do. We even have common practices concerning that, such as removing a tag completely as "ambiguous" or saying on the wiki "This is for meaning A; for meaning B, use this other tag".
Apparently there's no way of knowing exactly how much the slashed abbreviations are used. I can only assume they are used to some extent, since they are common practice on Danbooru. (Interestingly, as a comparatively rare big example, zettai_ryouiki has 24,400+ posts and the shortcut /zr. It's reasonable to assume that not absolutely everyone who populated that tag was interested in typing everything accurately or installed the autocompletion. Maybe, some times, they made use of the shortcut.)
By the way, I suppose typing /acos (four characters) is easier than making alternate_costume appear in the autocompletion, since you should type at least "alternate_cos" or some down arrows because there are multiple other tags that begin with "alternate_".
And, I don't use the auto-completion, because AFAIK it makes me press enter twice always, which is annoying.
This is something that has been on my mind for a while now: How about a tag for alternate_legwear? Relevant images could be like post #1069332 and post #350913. Would there be any validity for this tag?
The DanbooruUp Firefox extension (forum #22135). Allows you to start typing in tags, and it will auto-predict for you based on the tags currently in use. That way you only need to type three or four characters plus enter to get the tag you want. It's very useful, even if that's the only feature of the extension I use anymore.
The reason it was done client-side is because it's much friendlier to have a mini copy of the tag database on the end user's machine that can be accessed locally than have every user continuously ramming the one database on the site's back-end every time they pause while typing.
If I remember correctly, shortly after this extension was first released, very early in Danbooru's history, Albert did incorporate tag auto-completion into the site itself, but it was almost immediately reverted since it caused the database to continuously time out.
Batch alias/implication functionality breaks if spaces are used instead of underscores. I try to manually find&replace when submitting but miss some. If you can include underscores in tags when suggesting instead of spaces, like you did in the rest of this post, that would be helpful (less chance of me missing one), since probably half of the jobs I put in are your requests.
Did: create alias /ahw -> alternate_headwear create alias /aec -> alternate_eye_color create alias alternative_eye_color -> alternate_eye_color