I do, but folks are promoting their stuff, hoping to make a sale, they are not there to find someone else to read.
And, well, I rarely get likes or retweets when I advertise--honestly, I think people are actually less likely to want to read you if you advertise your book, no matter how clever a quote or a pitch I put in.
There is always this dead silence apart from my already existing nice friends.
The other day, i hit my Twitter best with 167 people liking my first line from the 'Write the first line for a novel inspired by this picture" and that made zero difference in people looking at my profile/links to my books. Only 3(!) out of these 167 people retweeted my line. Probably zero of them visited my profile.
Social Media just baffles me. I end up talking about what interests me on Twitter, but it doesn't translate at all in my readership numbers.