2. YouTube is a video-sharing website headquartered in San Bruno, California.
The service was created by three former PayPal employees in February 2005.
In November 2006, it was bought by Google for US$1.65 billion.
Anyone can post a video on YouTube. It is absolutely free to upload a video
there and make it available for anyone on the internet to see.
3. Twitter is an online social networking service that enables users to send and
read short 140-character messages called "tweets"
Users who are registered to twitter can both see and post tweets if they would
like. Those who are not registered can only observe tweets, unless a certain
page is private.
Users who make their twitter pages private, can control who they want to see
their tweets and their information.
Twitter
4. Vine is a video sharing service that allows the user to make 6 second videos
that loop continuously.
It was acquired by Twitter in October of 2012, before it officially launched.
Users are able to create and post videos as well as view videos posted by
others. Like twitter, users can make their information private as well.