R-E-S-P-E-C-T !!!!
Here is an interesting concept that was brought up at one of the company meeting's. What makes people respond to a email invitation, a call, a interactive campaign or any other kind of tool that companies use to generate new interest in a marketplace
The core to anyone's response is respect. Respect of intelligence, respect of the other person's time and the fact that we are all exposed to the same media asking us to spend money in one form of media or another, so your target audience is just as savvy as you think you are about these things.
For me and what I do, I know that I am calling people in the middle of their very busy day, so I am the one intruding. I know I have to be respectful of their time and the task I have just interrupted. There is nothing worse than getting a call in the middle of dinner by someone who is trying to sell you something and not understanding that your food is getting cold! It is the same with calls in business, if I call someone who is running out the door to a meeting, it is only polite to excuse myself and let them know when I will call back. People respond to that kind of respect, and when you call back they remember that about you so you, have something in common from the start.

Great advice Jennifer! You
Great advice Jennifer! You are so good at what you do!