YouTube

I would consider YouTube to be a well-established communication website. As most people know, one can create an account, post videos, and have those videos "liked," "disliked," and commented on. One can also do all these things on other people's videos as well. Youtube puts ads on everyone's videos as well as charges users for a premium accounts so that they can post videos longer than 10 minutes, and this is how they make their income.

YouTube is also now in a partnership/ownership with Google. Every time one logs into YouTube it asks the user to merge their YouTube account with their Google mail account. This opens up the opportunity to send mail to the users gmail account as another means to make income through mail advertisements.