Note: Most of the stuff in this post I learned from Roy H. Williams. Please forgive me for stealing.
Okay, you've made one point, spoke to the heart, made it relevant, and didn't look or sound like an ad. Yet, the needle isn't moving. No one is remembering your message, let alone acting upon it. Why not?
Three Levels of Memory
Everything that happens throughout your day is put into electrical or Working Memory (think RAM like a computer). At the end of the day all of your Working Memory that wasn’t relevant or impactful is erased by sleep, including stuff only slightly relevant or impactful.
Declarative and Procedural Memory are chemical memories. These are stored in your brain (think hard drive). They come from repetition. Declarative is the memory of things you can recall if asked (your cousin’s phone number). Procedural is memory that comes without thinking (slamming your brake when a deer crosses the road)
Frequency is Key
With repetition, electrical Working Memory is converted to chemical Declarative memory, and as repetition continues, from Declarative to Procedural.
The amateur practices enough to get it right (declarative). The professional practices until he cannot do it wrong (procedural).
Hitting the Nail on the Head
Another way to think about it is the hammer and nail. If you hit a nail one time, it will make an impression in the wood. But then the big claw called sleep rips that nail out, leaving just a hole. If you put that nail in the same hole, however, and hit it again, the hole gets deeper. Keep putting the nail into the same hole and hit it over and over and eventually sleep will not be able to rip that nail out.
Some of you might argue that you can pound a nail in one stroke. Sure you can. How many of you know exactly where you were when you heard about 9/11? That happened only once, but the impact was big enough to push it directly into declarative memory (plus there was the added frequency of it being talked about for months on end).
Your ads will not be as impactful as a terrorist attack or space shuttle explosion.
The Magic Number
In advertising, the magic number is three. It takes the average person hearing/seeing an ad three times in seven days before it gets stored as Declarative Memory. And they must hear it three times every week until they need the product or service. And when I say "hear" I'm talking about actively engaged in the ad, not the subliminal effect of background noise.
To get that kind of frequency you need to put your message out there as often as possible. Whether you use TV, newspaper, radio, Facebook or Twitter, your success will be tied to the consistent and constant use of the medium every single day. Otherwise, you are just spending your advertising time and money foolishly.