I don't believe they "work", but IMO as a company you want as many way to push information to your customers. Today it's principally emails or notifications. An

I don't believe they "work", but IMO as a company you want as many way to push information to your customers. Today it's principally emails or notifications. And so this is why you see newsletters form and every apps under the sky seems to ask to enable push notifications on your phone. Another way is RSS feeds, but many companies seem to consider that there's not enough users for the trouble.