Based on my experience, as noted above, it's a crapshoot. In general, any DM ad will only be successful (as in someone calling the direct response #) when all of the following three things happen simultaneously at the time of the ad running:
- The listener is in a demographic which the ad targets; this is not necessarily age-based, as a case can be made for a demographic called "timeshare owners", for example.
- The listener has a need for the product being advertised. (Duh, right?)
- The listener hasn't already been in the market for the product and feels there are adequate local (as in "why should I call in and talk to someone in a call center somewhere when I saw a billboard for a local attorney yesterday offering the same services?") sources for whatever the ad is hawking.
Given all that, it probably doesn't surprise anyone that I am
not getting rich running DM ads, but they fill holes and if one has holes to fill, one may as well fill them with something that has even a slight chance of providing revenue.