instead of just supporting the standard #hashtag
why not also support suhhashtags?
e.g. #world#country#city#event
or maybe this form looks better?
e.g. #event:city:country:world like #Rio:2016:Olympics
it would be more detailed, and would allow for degrees of searching. e.g. you can search for #world#country1 or #world, without interfering with #world#country2
To take this further, you can still support searches of both #world#country1 and #world#country2 by perhaps using ## instead. Where the number of hashes defines the 'level' of the tags.
e.g. #world##country1##country2
EDIT IN RESPONSE TO MIKED:
hmmm... what don't you get about it?
Its so you can assign a 'relation' to a post.
e.g. when you want to say that your post is about NEW YORK that exist in USA, you say #USA#NEWYORK . Hence anybody who searches for the tag #USA , will see post that contains hashtags of either #USA or #USA#NEWYORK
Other applications. Geohashes that are searchable from twitter in 'degrees'. E.g "N 12° 20' 44", W 98° 45' 55"" could be subhashed as #geotag##N12###20####44##W98###45####55
where the same number of hashes indicate that the two subhashes are 'level' in the pecking order.
The GPS example is admittedly unwieldy, but the capability is there. However I only expect people would require at most 3 subhashes.
e.g. #event1#team2#task3#subtask4 - for a group that is working on a specific task.-- mofosyne, Oct 17 2011 long time no see, oh short-one-with-hands-on-hips. I'd comment on your idea, but I have absolutely no clue what it is about.-- MikeD, Oct 17 2011 Have a look at the edit I made, I provided more examples.
But tl;dr: Subhashtags is about emulating the multilevel categories feature that you often find in many websites in hashtag form. E.g. the categories of Stationary>pens>color that you find in shopping stores.-- mofosyne, Oct 17 2011 [-]-- FlyingToaster, Oct 17 2011 FlyingToaster, Oct 17 2011
[ D: ]-- mofosyne, Feb 24 2012 Unless you have many occasions where there's going to be not only a France:Paris but a Paris:France it's sortof irrelevant in one of those newfangled databases; as long as you get people to enter the tags, having them ordered is non sequitur to most queries.-- FlyingToaster, Feb 24 2012 random, halfbakery