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.