These people could be trying to give you money but you can't understand a word they are saying. My guess is that they are the most unsuccessful company in history.
Both, Mark of 27 Apr 2011, and Mark J of 26 Sep 2011, are correct. As much as you might not like it, your number, as some time in the past, became voluntarily associated with a free trade magazine. They cannot be touched by the FCC. The Do Not Call rules specifically exclude them from calling unless you tell that particular magazine (or publisher) to remove your number.
Understand that I hate these calls as much as anyone else; but, in my case, I brought it upon myself by subscribing to the magazines. No, I did not specifically give them permission to call me, but the law allows them to do so.
I called them back and got a recording. It said who they were and what they do ("... a teleservice company who qualifies correspondents free of charge." -- or something to that effect. I think they also used the word "survey" in the recording. I left a message, asking for them to call me back and tell me which publication(s) or publisher that they have my name for. Also please remove my number (mentioned a couple of times).