I don't think this trend will last, though. If a user denies the notification request then the site is never allowed to ask again - the user has to manually enable the permission. People are going to learn quite quickly that if you don't put the request in the context of a specific action you're screwing yourself over.
That said, I wouldn't mind it if these prompts could only be shown in response to click events. Small downside, but it would stop the request spam quite effectively.