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Disclaimer: This is a joke. Don't sue me.
Skip the Proofreading
The world has changed and so has publishing. The modern writer needs to get ahead of the ball in order to make it. Proofreading is one of those old-school concepts that should be buried with yesterday's underwear.
The problem with Proofreading is two-fold:

Proofreading takes time. A lot of time. You may be able to write a novel in 30 days, but this proofreading, and editing, and other nonsense will take months, maybe years.
I have one word for you: time to market. -- okay, fine... it's one phrase.
Advantage #1 -- You get your book out there as soon as you are done!
Finish fast, publish fast. That should be your motto.
Don't sit around waiting, pondering, improving. You writing is a work in progress. Get it out there... which leads to the other advantage...
Fold #2
Writing of the 21st century needs to be collaborative.
Once you've proofread your manuscript you have effectively excluding your customer from the process. Dear writer, who is your customer? The reader.
People finally understand that Social Collaboration is the most powerful way to connect with your customer.
Imagine how wonderful your readers will fill if they find your mistakes.
Imagine your reader informing you via Twitter: "Page 1, Par 3, Sentence 3 -- You wrote *beat* instead of *bet*"
Then you thank them, maybe even retweet it.
Your reader will feel connected to you and your writing. They will be your fan for life.
Don't be selfish. Share your work and the process with your fans.
Advantage #2 -- A personal connection between reader and writer
You have a choice. I've shown you what's behind the door. It's up to you to walk through it, or pretend you don't know the truth.
Now, go and write!