Copywriting Grammar Ain't Perfect
Break the rules. It's OK. You're not writing for your high school English teacher. Present your copy in a casual but professional way.
http://www.entrepreneur.com/article/198294
Copywriting Basics: Giving Grammar a Break
Copywriting doesn't necessarily demand the strictest observance to formal English grammar. Because your objective is to build an empathetic rapport with your readers, you want to write the way they speak. Depending on the circumstances and
your intended audience, using slang, sentence fragments, contractions, colloquialisms, and so on is perfectly acceptable...
http://www.dummies.com/how-to/conten...r-a-break.html
ABC Copywriting: Five grammar rules it’s OK to break
http://www.abccopywriting.com/blog/2...ts-ok-to-break
Those who have a problem with it, aren't the audience targeted for a specific public. What that means, it was not written for you.
I don't see it as any different than a salesman ( copywriting is selling basically) changing up their clothing and lingo if they are selling to grease monkey in a car repair shop or a corporate exec, academic or any other public. It's who your public is and if they will respond and trust you.