I have a couple of Zapier zaps set up to alert me of hot posts in a couple of niche subreddits. I use these alert mostly to inform my thinking and content for a blog I'm working on. It helps me decide what content will add value as I can see the type of questions people are asking, and it allows me to promote my blog as I can reference it in comments / answers.

Most of my interaction with Reddit is driven by these alerts.