The User Profile holds all of your information that you would like to share with the community and the world.  A good way to introduce yourself and get to know a bit about other members, everyone really should take the time to flesh this out.  Even Tourists get some space for self-expression here!

Wikipedia states:

The Notifications module currently allows the system to send email that helps keep up to date with recent site or content updates.  The system will not send more than one e-mail per day and will only send them if there is something to report.

In this case, no news is bad news.

This is what it says it is:  click Edit when you want to make changes to your profile or your basic account settings.