...having found your service by chance, we've been completely happy and pretty surprised actually. You offer a lot of features, with a very reasonable & logical rate system. ...How much your service will help is possibly beyond your understanding, but I'm sure you've heard that from other people using your service.
It has always been a pleasure dealing with you.
My company is unhappy with Yahoo and the advertising that they put into our monthly newsletter. In searching the web, I came across your site...Thank you again for your service...