What’s odd to me about people using hashtags in changeset comments is that they aren’t natively supported by the OSM website, they are not clickable or searchable. When I see something like #starbucksmapping I expect to be able to click it and be taken to a list of all changesets using that hashtag, or ideally, a page that tells me what it means (e.g. a Wiki page describing an organised edit).
When people started using hashtags in tweets, Twitter implemented hashtag search. Does OSM need the same?