how to show more information in user's profile
For things like last 10 posted content, I believe you can use contextual filters in Views. With that you can create pages like /user/somebody/posts where Views will show you the last contents of user for example, also I believe you can make a block out of such a view that you can place on profile pages.

Also it may worth for you to check out the Profile2 module, you can create multiple types of profile pages with it for example.

http://drupal.org/project/profile2