I’m a reviewer, so I mostly find books to read from NetGalley (which is hardly a social media site), or from other reviewers (e.g. through the weekly First Line Friday posts).
But I do occasionally find books to read through social media—although those posts are often links back to a review blog.
My favourite social media site for personal use is Facebook, but I rarely find books to read there in my general feed. That’s partly a function of the people I follow. I use Facebook to connect with real-life friends and writing friends.
However, I often see great recommendations in the Avid Readers of Christian Fiction Facebook group. If you’re on Facebook and looking for Christian novels to read, then Avid Readers is the place to go. You can post a request for what seems like an oddball book and dozens of recommendations. (I don’t post requests because there are too many books and too little time.
More often, I find books on Instagram (as I tend to follow readers and reviewers there), or on Goodreads. I guess that’s not surprising: that I’d find books to read on a social network dedicated to booklovers. I’m also a member of Litsy, but follow a combination of people there (i.e. not just Christian fiction readers). That means they’re often recommending books I’m not interested in.