I don't always encounter alt text for images on Mastodon. But when I do, I notice the alt text descriptions are higher quality than they were on Twitter. In general, I feel like describers are sharing the intent of images more and sharing their visual interpretations more often. When describers do this, the pictures come alive in my mind. In short, alt text feels less robotic on Mastodon and more like my sighted friends narrating their lives and observations to me. It's really awesome and special to watch. Keep up the great work, describers!