I've used several sites like StackOverflow that use the automatically generated images from Gravatar, and they really do make the site more pleasant. Additionally, they make it easier to visually follow who posted what in a discussion.
The one difference (unless I misunderstood the article) is that these sorts of images are generated randomly from a hash and so are basically guaranteed to be unique. I think this is a big advantage as having two identical avatars in a discussion would just make it visually confusing to see who is who.
[1]: http://robohash.org/
I've used several sites like StackOverflow that use the automatically generated images from Gravatar, and they really do make the site more pleasant. Additionally, they make it easier to visually follow who posted what in a discussion.
The one difference (unless I misunderstood the article) is that these sorts of images are generated randomly from a hash and so are basically guaranteed to be unique. I think this is a big advantage as having two identical avatars in a discussion would just make it visually confusing to see who is who.