Direct Mail Without Call Tracking Is Just Silly

http://www.dmnews.com/direct-mail-without-call-tracking-is-just-silly/article/310903/

There's no rational reason why anyone should spend a dime, dollar, or penny on direct mail and then fail to use a call tracking number on the direct mail pieces themselves. Call tracking numbers provide incredibly valuable data about which mailers produce calls.
Not only can they tell you which ad copy, colors, size, CTA, geographic targeting efforts, and offers, produce calls—they can tell you which don't. Can you say optimization? They're also really easy to implement on direct mail pieces. You're putting a phone number on their anyway, right? You might as well put a phone number that gives you data.
Now let's talk pros and cons.