Just to clarify--

In the music industry parlance, a distributor is a person or organization that purchases recorded material from several sources, and sells to retailers, who pay a modest upcharge for the ability to place a single large order (consisting of several different titles) rather than having to contact individual publishers (or artists) with a lage number of very small orders.
   CDBaby isn't really a distributor, in that sense: they don't provide a discount from retail prices unless the artist/publisher specifically provides such a discount.
    The advantage of CDBaby to the artist is obvious--it provides exposure and a place for customers to order CDs that would otherwise be unavailable. Its disadvantage to the artist is that it effectively closes off all other avenues of retail sale.