Oldpoet: An old friend of mine who was the editor of a Riverside, California paper always answered petty complaints regarding spelling and grammatical errors with the comment "you should see how they spell "shirt".....  Of course we should try to use correct grammar and spelling.  They contribute to clarity.  Additionally, misspellings and grammatical errors give individuals who disagree with the content of your message a basis for "cheap shot" attacks on the message.  

Usually those mistakes don't really alter the meaning of your message, but it's nice to avoid them.  So be careful how you spell "shirt."  regards, Gary