What are the similarities between professional writing and personal writing?

Professional writing can be defined as business writing, media writing, and writing that takes place in or for the workplace. Personal writing is considered writing for any other purpose oriented toward the individual writer’s needs. Advice available on writing dissects the writer’s capabilities to put words out effectively styled for clarity through such items as vocabulary choices and tone of voice, but style issues do not separate professional writing from personal writing. Professional writing and personal writing differs in intention, composition, and exposition.

Professional writing can be defined as business writing, media writing, and writing that takes place in or for the workplace. 

Personal writing is considered writing for any other purpose oriented toward the individual writer's needs.