Fediverse

For a long time, users have been able to submit microblog-style posts to link-aggregator subs (a.k.a. subcommunity, community, magazine, etc.). Some platforms such as mbin require you to select one for your post. Previously, I've thought this sub selection as a special hashtag for the post. However, I've recently been reminded that posts actually show up in communities as full-on threads. So what do you (or the threadi gods) consider to be proper etiquette in selecting a proper sub to make your microblog post to? There's always !random, but that feels kinda worthless...