ability to configure the default profile used for anon users

[soph-sol]

I'd love to have the ability to configure the default profile used for anonymous users, so that when people visit my shared bookmarks page, it's set up to display information in a way that's helpful for the kinds of things I bookmark.

Specifically I'd like to be able to set how many lines of the description are visible, as well as add custom CSS the way I can for my own user profile.

[bloodripelives]

This would be great!