[why-el]

This is what my strategy is more or less, but for emails. If a startup sends me a "Welcome to X", I treat it as "Don't forget to unsubscribe from X".

[version_five]

This is a good idea. I almost always get caught by this. Last week I had to make Notion account for something, immediately started getting daily spam from them. It's the same everywhere, they think signing up is somehow a license to spam. It has the opposite effect, it destroys any good will towards the company.

Slack is another big offender. Every time you sign up to a new channel you're back on a spam list for some reason. I don't know who is coaching these people, but like notifications, it's a big reason why I often just don't bother signing up for stuff