postcard mailings vs letters

Hey everyone, its David here. I had a weird lead source today. i have a series of postcards i send out to people headed into foreclosure and this lady called us off one but she owned the home free and clear but it was a rental so i assumed she was late on her own home. nope, turns out she works at the post office and saw a postcard and copied down our #. now that wouldnt have happened sending out letters. just a little tidbit i though you could use.