Removing any friction for new users or players is such a huge deal, more sites should embrace this approach. Similar to how Facebook created ghost users for everyone, why not make this explicit? There are a number of plugins for popular web frameworks that create temporary user accounts for each visitor, allowing them to use the site just like a regular user. This way it's a bit more sophisticated than plain old sessions which allows it to be integrated in existing sites as well.

And if the visitor abandons the site their data will just be garbage-collected after a while.