First mistake is talking to him too long. When you checked him out first time, you should have said no thanks and closed and locked the door.
I agree. When you're answering his questions, he's in charge---not you. It's called being "interviewed", "sized up", or use your own term.
Criminals do it, used car salesmen do it, panhandlers, etc. All people who want something from you.
Interesting that so many assume that he was a magazine seller just because he said he was. Or that, even if he was, that's all he was.
Most outfits hire clean cut kids, not dingy looking "ghetto types".
I remember an episode of Dale Hinman's show, (Body of Evidence) Court TV, in which a man with a long criminal record signed on with a magazine subscription company just to gain access to women's homes. The rape and murder he committed after casually walking thru the neighborhood, and TALKING his way in, was the subject of the episode.
Magazine subscription selling gives people a good opportunity to case your place and check you out in case he/she/they want to do a burg sometime when you aren't (or maybe are) home.
Yes, I know, I'm paranoid in my later years. I live in a semi-rural area and don't approach the door without a pistol real close, and don't answer strangers' questions.
Of course, I can be a sucker for Girl Scout cookies, or helping school kids raise money for a good cause.