It appears to be a newer program that enables you to send messages to their lists.
Cheap trial fee, with reasonable monthly fees.
I am not naive. I know the response rate to these mailings won't be huge.
However, they also allow you to upload your own list.
Please only responses from people who have used this service.
Not people who are just opinionated and want to relategroup it into some other company they didn't have any success with. Or affiliates trying to promote it.