Updated 10-8-2013
Update at end of blog post.
I this installment of Dante’s blog I thought I would share with you a few writing tips.  These tips were given to me by a friend.  I’m in no way the originator of these tips.  The tips I will share with you today involve the usage of En Dash, Em Dash and Ellipse Marks.

En Dash versus Em Dash
There are many uses of the en and em dash and also many ways to form these dashes using your computer. The following explanations offer the most common uses and methods for forming these dashes.

En Dash
An en dash, roughly the width of an n, is a little longer than a hyphen. It is used for periods of time when you might otherwise use to.

Examples:
The years 2001–2003
January–June

An en dash is also used in place of a hyphen when combining open compounds.

Examples:
North Carolina–Virginia border
a high school–college conference

Most authorities recommend using no spaces before or after en or em dashes. To form an en dash with most PCs, type the first number or word, then hold down the ALT key while typing 0150 on the numerical pad on the right side of your keyboard. Then type the second number or word.

Em Dash
An em dash is the width of an m. Use an em dash sparingly in formal writing. In informal writing, em dashes may replace commas, semicolons, colons, and parentheses to indicate added emphasis, an interruption, or an abrupt change of thought.

Examples:
You are the friend—the only friend—who offered to help me.

Never have I met such a lovely person—before you.

I pay the bills—she has all the fun.
A semicolon would be used here in formal writing.

I need three items at the store—dog food, vegetarian chili, and cheddar cheese.
Remember, a colon would be used here in formal writing.

My agreement with Fiona is clear—she teaches me French and I teach her German.
Again, a colon would work here in formal writing.

Please call my agent—Jessica Cohen—about hiring me.
Parentheses or commas would work just fine here instead of the dashes.

I wish you would—oh, never mind.
This shows an abrupt change in thought and warrants an em dash.

To form an em dash on most PCs, type the first word, then hold down the ALT key while typing 0151 on the numerical pad on the right side of your keyboard. Then type the second word. You may also form an em...

Ellipsis Marks
(I see ellipsis marks that are incorrectly used all the time. Please read these ellipsis marks rules and apply them to your writing. Do not use ellipsis marks as a pause, the correct punctuation for that is a comma.)

In grammar and rhetoric, the omission of one or more words, which must be supplied by the listener or reader. 

Ellipses signal, in addition to elision, a faltering or trailing off (in which case they are sometimes called suspension points), but to prepare the reader for an abrupt break or interruption in thought, use an em dash.

The primary function of ellipsis marks are to omit one or more inconsequential words from a quotation, as in these examples:
"Four score ... our fore fathers" 
1,2,3,4 ... 10.

Think of it as yadda-de-yadd or blah-blah-blah.

(1) Ellipsis and em-dash in dialogue:
“Jonathan, please, what I meant was…”
“What? What did you mean?”

Compare the above to this:
“Jonathan, please, what I meant was—”
“I don’t want to hear your excuses. It’s too late.”

Can you see how the first example is the first speaker trailing off and the second example has the first speaker being cut off?

(2) In dialogue use an em-dash as a pause/break that does not represent omitted words:
There it was again—that loud, terrifying scratching.

Update.
I have been made aware of an issue involving the Em-dash on Macs using the Scrivener software. for further information check out Michael Corbin Ray's blog on the subject.  
http://michaelcorbinray.com/news/2013/08/30/a-bug-to-watch-out-for-em-dash-close-quote-in-scrivener-for-mac/

Each and every one of us leads two lives.  An outer life that we show the world and an inner one that we show to noone, not even those closest to our hearts.  The simple fact is that the outer life is a lie.  A facade that we hide our true self behind.  Why we do this is simple.  We do it to protect ourselves from harm.  Despite this need to keep out inner life secret we still want to show it.  Most of us don’t ever have the opportunity to expose this inner self, yet still keep it safe and protected.  Writers of fiction do have the opportunity to do this.  We can tell our inner most secrets to our audience of readers and not have them realize we are doing it.  How you may ask?

We lie about it.  We turn our secret self into a lie and display it for all the world to see, but because it is a lie, like all fiction is, our secret is kept safe.  Through these lies we breath life into the words we put down onto the page.  We bare our very souls for all to see, yet cloak our naked soul in the guise of something else.  Our readers see a bit of themselves within what we show them.  Through the lie about our secret self we show them a bit of themselves.

We must never reveal the truth of our secret self that is hidden behind these lies for the structures we have built with them will crumble away as the stones of truth are pulled away.  The revelation of what lies in our secret life dramatically effects how the reader perceives our writing.  A bit of Charles Dickens’ secret life was revealed by his biographer, John Forester.  He discovered that as a young boy Charles Dickens was force to work in a shoe polish factory to help pay of his families debt.  Twelve year old Dickens labored in the factory pasting labels on bottles of shoe polish from eight in the morning until eight at night.  Despite this grueling work his father still ended up in debtors prison for months.  Dickens was shamed by these events.  He pulled them deep into himself, making them part of his secret life.  If it hadn’t been for a chance encounter by his biographer Dickens would have taken these secrets to his grave or would he have.  He was a writer after all.  He laid bare this horrible secret in his writing over and over throughout the years.  A prime example of this is the character David Copperfield.  Copperfield initials are D.C. while Dickens are C.D., but the connection doesn’t end there.  Copperfield’s guardian ends up in debtors prison while he ends up pasting labels on wine bottles in a winery.  One of the major changes that Dickens made with the Copperfield character is that he made him an orphan.  This change appears to be the greatest insight into Dickens’ secret life.  The shame of that singular event in his life was so great that when he put it into his writing he killed off his parents.  Perhaps during that time Dickens felt like the orphan that he made Copperfield into.  We will never know the answer to that question.  Dickens swore to never speak of that moment again after he wrote a note to his biographer about that event in his life.
Now I think you can see the danger to revealing the truth hidden in an authors secret life.  The revelation forever alters your perception of their work.

During the course of working on this blog I had a profound and painful realization about my own secret life.  It had to deal with a reoccurring theme in my writing.  I will not expose any details about this revelation here or ever.  I will say this though, understanding a truth about myself will help me grow not only as a writer, but as a person.