Purchase compiled lists to reach your target market when response lists aren t available. If you would like to mail to only the people who make the little tiny screws that fit in your eyeglasses, there s a list out there, somewhere, with just the names of those folks on it. It may be a short list, but it s available. Between the different list houses there are also significant differences in pricing, return policies, and freshness of lists and names. Some vendors clean their lists more frequently.
Different vendors offer different service levels, too.
Each list house has its own counts and numbers for different selections, and each treats merged data in different ways. Most list houses have their own particular specialty - so it pays to shop around. When you need a great mailing list, just dig.