What I observe on vast of the majority of the news websites and not only them, is that they are sending all kind of notifications (Apps, Twitter, Emails etc.) when possible, 10 AM, 2 PM, 11 PM, 1 AM.
That's not right, know your audience, look at your analytics, check most valuable hours, think when you want those notifications, ask friends etc.
If you are not thinking about that, not knowing your audience, it is time to start doing that.
Why? Because you can disappoint your users, for example when you publish something to Twitter or you send an email at 1 AM.
Believe me, users will stop their subscription to your Twitter tweets or will unsubscribe from your newsletter and they will not read. You are not leaving a good impression like that.
In general try to think as a real customer, ask friends and make A/B tests.
Send one email, ok at 1 AM to half of your users, then check how many of them opened it, read it and clicked on the links in, then do the same with the other HALF but in a different time, for example, 9 PM.
All big websites are doing that, why you are not doing it?