An interesting little piece from Huffington Post on how weddings looked, and were booked, in the 1970's : What Weddings Looked Like in the Old Days
"Our last stop was the photographer. We overlooked the yellowing pictures and plastic lilacs on the dirty ledge in his storefront window. My mother knew someone who knew him. "I heard he's nice," was her complete report. He seemed happy for the business."
Most brides booking their photographer now will have a few other criteria on their list - the photographer's style, their range of albums, and (especially for those wary of doing business online in a 'faceless' environment), whether they have a studio where you can meet them and see their work properly.
But maybe "I heard he's nice" should still be in there somewhere?