In the beginning was the ‘vanity press’.  You paid to have your book printed and paid for copies which you then sold.  Now there is ‘self publishing’.  You still pay a fee but a team of experts walk you through the process assisting you with editing, cover design, interior design, listing your book with the big wholesalers such as Ingram, listing your book on Amazon and Barnes and Noble, electronic editions such as Kindle and Nook, and finally marketing.  You retain 100% control and 100% of the rights of your work.  A number of authors who have published through traditional means have turned to self publishing for this control.  They have already made a name for themselves and like the idea of controlling their work.  So what is the benefit of the traditional way?  MARKETING!  The traditional publishers will do the work for you of getting your book out there and getting your name known.  They set up book signings and so forth.  I think it is much easier to make money if you go the traditional route.  However, you lose control of much of your work.  And the publishers retain the rights to your work for years.  A tough call!