>When I do end up talking to a telemarketer, I
>politely say, "No, thank you," and hang up.
If they are also talking to other people in your market, that's a waste.
Sales people can be a great source of information, by calling around a list, they take the temperature or measure the mood.
Domestic calls are another matter!
The double glazing pitch now is "we have consultants in your area..."
"Thank you for the warning, I'll have a shotgun ready"