Conversation

Good: Posting, in your own spaces, the importance of including #AltText in media.

Bad: Going to other people's posts and distracting from the substance of the post by saying "this needs alt text" or even outright shaming people for not using it.

The former contributes to a culture of accessibility. The latter contributes to a culture of hostility - and not only will it not make people use alt text, but it will simply discourage them from posting altogether.

Same goes for content warnings. If something isn't CWed like it should be (that is, if it actually breaks the rules), quietly report it to the instance admins and they will deal with it.

You want people to come to Mastodon because it's different from #Twitter. They're not going to want to if you welcome them by nagging at them about things that they never had to think about on Twitter. Yes, those things are important, but you will be more successful promoting the culture you want to see than you will by trying to badger people into ticking all the boxes you want.