Richard, I can almost guarantee that I have several more coming in from that 100 alone.
My card is posted earlier in this thread. There are a couple of things working in my favor. I paint children, I have 3 between the ages of 2-6 so I started my list from their play school classes. I live in a small suburb of Charlotte where you will find most people have portraits done of their children. I then contacted a couple of previous clients, one showed up with a list of all of her old sorority sisters with young children. This list was great because it got me out of just my town. It is sort of a situation where they all have to have what the other one has
Her list was a little gold mine. The mother of the last portrait I did (Lydia in unveilings) is in Atlanta, she is so excited about hers she wants more, and she emailed me yesterday to tell me she had four other friends that were planning to call. The brother sister pair has also resulted in another contact not on my mailing list. This word of mouth thing is great!
I'm not exactly expensive, so that makes a sale easier I'm sure. I doubt I would have gotten this sort of response, if any, had I just mailed out postcards to people that had never heard of me.