Trying to answer above question - Thanks very much for the help!
Using MapPoint to determine Marketing Universe by Zip Code - We send the ZipCodes to a Direct Mail Company that in turn mails our Mail Pieces.
I am worried that MP does not show all possible zip codes. For example in MP Philadelphia shows as 20 zipcodes - but zipcode.com shows 87.
If I only mail to the 20 zips in MP will I still get all of Philly?