Keywords of your blog,overviews of Traffic sources,and where from you got visitors.In audience tab shows page views by countires,browsers and by operating system,as like Googe analytics.
You will get instant page views and other details about your websites.This will help you to promote your website. And you can which page getting more visitors .Stats monitors and analyze each page views and brings you instantly.
It is so simple and easy to understand.
There is no need of Sign In, as it consist as gadgets inside the blogger ,as under stats tab.