I just went through https://phabricator.wikimedia.org/T123529 and think its focus on URLs as a way to provide hashtag functionality is one way that could be useful for supporting campaigns involving Wikidata, where most manual edits do not currently have hashtag functionality (thus precluding campaigns like 1Lib1Ref on Wikidata), and tool-based Wikidata edits are tagged by tool only.
A range of other ways could be thought of:
- A dedicated set of tools (e.g. as used in https://www.wikidata.org/wiki/Wikidata:Menu_Challenge/participants ) but more easily deployable by others
- Some abstraction of verbal descriptions as in https://en.wikipedia.org/wiki/Wikipedia:WikiProject_Computational_Biology/ISCB_competition_announcement_2016
- Something tied to a specific set of items/ properties/ references/ constraints
- Something tied to hashtags in other ways, e.g. as per https://www.mediawiki.org/wiki/Extension:Education_Program
- your idea here