This means the timing of the pieces should be close enough together that the repetition is a noticeable pattern. I’d say more than 2-5 days apart would be too far to build the effect, but simultaneous might play out as contrived.

There are plenty more mediums to explore beyond email and postcards. Don’t forget television, radio, billboards and other avenues as well.

In the linked study, the email and postal mail campaigns seem to have been targeted to hit at around the same time, though this is not clearly stated in the article.

I can’t offer any insight about the ordering of messages through different channels, because I haven’t run or read any tests myself, but perhaps others can chime in with any experience(?)

Regardless of the order, as this article suggests, the most important factor in success would seem to be coordination:

* Using each as a medium to communicate the same campaign
* Making sure we’re sending through each channel to the same people

But of course, we can’t assume that each and every person is going to see or hear each communication just because we target them, so we may also want to make sure that each communication stands on its own two legs and we don’t take for granted that they’ve seen each of our other communications.

So, as for the pro’s and con’s, by virtue of coordinating through multiple channels we might maximize the pro’s - by hitting prospects with multiple touches through different mediums - and minimize the con’s - if one of our channels doesn’t make it to them or stick, maybe the other(s) will.