Purposes - Persuasive Writing:

Persuasive writing attempts to get readers to change their point of view and possibly to take action.  The writer wants readers to think a certain way about an issue such as the war in Iraq or women breastfeeding in public.  Or the writer wants readers to take action: to buy a certain phone, to stop smoking, to wear a motorcycle helmet, and so on. 

Therefore, the READER is the key focus.   

Political speeches, editorials, sermons, and advertising are examples of persuasive writing.