In the My References tab, you can sort the references, using the drop-down menu on the right of the page. A search function is available in the left column. In the Organize tab, there is a Find Duplicates function, to delete duplicates in your database.
You can create files (called groups) inside your database. A reference can be added to several groups, if necessary. Go to the Organize tab -> Manage my Groups, to create new groups. You can share a group of references with other persons.