Adventures in Epublishing - The Numbers

Even though writing is an art, it's also a business.  Some people are very interested in numbers.  I know I am.  I'm always curious to see what people have done to help measure what I'm doing.  Obviously, everyone's situation is a little different.  Some people have little in the way of friends/followers, but have still sold a ton of books.  I'm interested to see if my 'numbers' will actually