Some of my stories are popular, some aren't. I get comments from some people on my profile, via pm, or reviews. Honestly, I love hearing about people's thoughts but I'm okay without them. That being said, feedback does drive writers to produce more and better work usually. We learn through feedback, we get ideas and generally feel more positive when we feel others are enjoying our creations, which leads to more writing.
As a beta I usually support my writers by leaving reviews or forum comments, encouraging them personally, and sometimes talking up their work in chat, places like that. Writers as a whole need support on the site too. Checking out stories in the Sneak Peek forum, responding and participating in conversations about different aspects of writing in the Writer's Corner is also helpful. We always have things we can learn from each other about writing so it's great to be involved with the other writers on-site because that leads to enrichment for everyone.
GA Stories is a great tool for allowing readers to find what they want and the review system is relatively easy to use. At this time we have to link to the discussion forum in the stories but that was the same on e-fiction as well. I like that the authors information is clearly visible on their profile page, including likes and the story listing if they have them. All in all, my opinion is most of the features are there to make the site very supportive for the writing community, we just need to get more people participating. Stories don't promote themselves, writing doesn't get better if we don't work at it, and I ALWAYS want to know if there is a good story out there I might have missed reading.