As you begin to gain visibility and subscribers, don`t forget that you can do a "tiered" plan for the people in your directory.
So for example, you start by listing a business and their URL for free, but
that`s all it is...just a name. It`s sort of like the line-listing in
the Yellow Pages.
However, as people start connecting with those businesses, you could
offer them a paid space on your site, with a 1/2 page "ad" including an
image and description, phone and email contact.
In other words, you can do with your beauty-specialized directory, what
Yellow Pages is doing, and charge a monthly rate for the businesses you
Also you`ll want to have a forum on your site where customers of the
places in Detroit can recommend or not, review and offer discussion of
their experience with the various businesses.