Two other use cases spring to mind: - "GitHub: Let me know when this PR is merged" - "Store: Let me know when this item is in stock" Unfortunately I think it'

Two other use cases spring to mind: - "GitHub: Let me know when this PR is merged" - "Store: Let me know when this item is in stock" Unfortunately I think it's only useful if it works everywhere, so we can't rely on every website implementing it themselves.