Thanks .. and the reason I ask this .. in an enterprise set up .. many conversations are driven on hashtags .. communities or rooms are just too cumbersome and formal .. 

Being able to follow a hashtag allows me to follow a cross  conversation .. for example if I am in customer service .. people can respond to customer with #service .. then any agent can pick up the message and run with it .. 

as for spam .. that is a problem #nostr should anyway handle  .. it should not limit/restrict  the good usage ..