Someone who uses the site youtube.com to post video blogs, videos, and such.

The only job where you can rage all you want without getting fired

Someone who makes videos for YouTube as a career.

A person on YouTube with their own account that makes videos and/or watches videos on YouTube .

Some one who Vlogs (video blog) and post it to youtube. They are usually of people who walk around with a camera. Very entertaining.

A person that uses a site called YouTube and is either famous or just started a career

A miserable prick who doesn't want to find a real career so they sit in front of a computer ranting for hours until they get enough followers they can manipulate into giving money to pay their mortgage