I have just deployed a script and a mastodon bot which attempt to hashtag lemmy posts so that they are better discoverable in microblogging services.
Please check the README for the why and the how.
If you have a microblogging account, please consider following the bot account which will help its hashtags federate to your instance’s public timeline.
Many thanks to @jgrim@discuss.online for hosting the bot.
PS: If you have a mastodon account, you can reply to your posts on mastodon (just search for their url) and add hashtags to your replies. This will achieve a quick and dirty version of what this bot is doing
I think your proposal is reasonable. However it depends how exactly post tags will get implemented, which is still rather vague. I dont think it makes sense to implement federated hashtags before we have post tags in Lemmy figured out.
In any case your tool looks very useful as a stopgap, and can help to test how hashtag federation can work in practice.