>Almost all Applications and useful WWW site entry procedures require the evolved procedure of having to provide both user name + password. This I don't understand. Why not just a password ? The user benefit would be obvious.

It is extremly important to recognize the user. The Universal Thread, for example, is having a user driven session.

The combination of both allow us to have a unique field on the username and still allow a user to take the same password as someone else may have taken before. With only one field, this would be impossible. It's been a commen approach in networking for years.