In a recent blog posting, marketing genius (and entrepreneurial visionary) Seth Godin warned about the limits of communication:
“Knock, knock” is a fine guideline for what communications documents need to say, he says:
“The purpose of most communication isn’t to completely explain yourself–Too often, we get stuck relieving tension, making our case and closing the door on the discussion.
The purpose is to open the door to interaction, learning and action. ‘Who’s there?’ is a fine response to hope for.
Communication is a process, not an event.”
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More specifically, communication should not be an invitation to an event where all of the salient details (and then some) are outlined without a chance for the reader/prospect to respond.
For instance, I recall promoting my writing and editing services in a letter of introduction I sent to prospects, ten years ago. After I inserted the logo (in reduced size) and provided my contact coordinates, the body of the letter itself spilled onto a second page. Hmmmm, I thought, at the time. They do say “less is more. But . . . . . ” I thought the ideas were so important that I allowed a 1.25 page letter to go out via Canada Post (which I used to avoid anti-spam legislation)!
Only three out of about 25 prospects responded and for most, I don’t doubt, the length made the letter too much to process.
In more recent years, I provided a reference letter for a mentor who was nominated for an annual award. Then I recognized that human attention span and intensity are shorter than we may think: as a copy or content writer, you will be far more deeply involved in the service you describe than the assessors of it will be (and care to be)! Less truly is more—without exception—whether or not you have a logo that gobbles space!
Beyond that one page limit, too much content detracts from the reader’s impression. You don’t need all that detail! A finite promotion is not a legal report or government legislation!
As Godin says, “relieving” your tension as a writer, making a “foolproof” case are me-centred, not prospect-centred, strategies. 
Such writing does not stop with the “knock, knock,” but assumes the admission and meeting to come, all without the prospect’s consent!
Don’t delude yourself that you’ll “blow the reader away,” when you’ll more likely tire them out!
A cardinal rule of copywriting is to remember that the prospect comes first.
So when preparing your next cover letter, focus on the employer’s needs, not your own.
And when preparing your resume, don’t tell your life story! Only the highlights that pertain to the job posting will matter to the hiring committee. Think a maximum of two stories/storylines for a two page resume.
Leave all of your impressive ideas for the job interview (and for the job!) that you’ll more likely secure by keeping your document to a “knock, knock.”
And now it’s your turn: Have you read a communications document recently that fails to stop in time? Please share your experiences: I’d be delighted to hear from you.