User Panels shoots pretty high: it aims to provide a consistent, easy platform for the handling of user-centric information display. It's not about new storage mechanisms or anything like that - just about marshaling all that user content together in a sane, easy-to-use way. I'm hoping that this blog post can be a semi-official shout-out to the drupal community - an RFC, I guess.
user_panels comes out of a basic observation about Drupal: virtually every Drupal site has a different conceptualization of who users are, what their role is within the site, how they should be interacting with one another, etc. This observation helps explain why it's been so difficult to settle the question of how 'users' ought to be handled - most folks, myself absolutely included, are coming from the perspective of a particular use case. Even with deliberate effort, it's been pretty tough to get into a genericized head-space with respect to users. There are, I think, a couple reasons for this.