Kristina Chen (a.k.a YouTuber Tinaecmusic) is a webcam celebrity best known for singing karaoke versions of pop songs originally performed by 90s boy bands like the Backstreet Boys and N*SYNC. Since her YouTube debut in 2007, her performance videos have become a frequent target of ridicule and parodies on the web.
Corey Delany is a teenage party starter turned famous due to a television interview in 2008. This followed his reckless party that caused $20,000 in damages. His interview became the forth most popular video for it’s time and created a roller coaster of events for the 16 year old. The video became known for Corey’s snappy answers.
Chocolate Rain is a viral video created by Tay Zonday that launched him into Internet fame. The video has been parodied and remixed in thousands of instances, eventually leading to Tay himself appearing on a number of television shows including a South Park parody. At over 54 million views, Chocolate rain is among the top 50 most viewed videos on YouTube of all time.
Reaction videos are videos posted in forums typically as a response to the OP.
They are usually short sentences or phrases taken from a larger video (popular movies, tv shows, YouTube videos, etc.) that express emotion in a similar fashion to reaction faces.