I have installed an app called Pushover. Pushover is a simple push notification service. Basically, it will sent you an alert to your phone, tablet, etc when things happen on the site such as you get a Private Message, someone posts to a thread your watching, etc. To sign up go to External Accounts in your settings (link) Pushover is available for iOS and Android including Apple Watch as well as a desktop client. There is a free trial, and if you like it the app costs $5 for permanent unlimited alerts.