Twitter

twitter.com

Twitter is an online social networking service and micro-blogging service that enables its users to send and read text-based posts of up to 140 characters, known as "tweets". The service has rapidly gained worldwide popularity, with over 300 million users as of 2011, generating over 300 million tweets and handling over 1.6 billion search queries per day. It has been described as "the SMS of the Internet."

Facebook

facebook.com

Facebook is a social networking website with more than 845 million active users in February 2012, which is about one person for every eight in the world. Users must register before using the site, after which they may create a personal profile, add other users as friends, and exchange messages, including automatic notifications when they update their profile. Additionally, users may join common-interest user groups, organized by workplace, school or college, or other characteristics, and categorize their friends into lists such as "People From Work" or "Close Friends".

Flickr

flickr.com

Flickr is the best way to store, sort, search and share your photos online. Flickr helps you organize that huge mass of photos you have and offers a way for you and your friends and family to tell stories about them. The best way to learn about Flickr is to upload some photos, explore the site, join some groups and make some friends. Flickr is almost certainly the best online photo management and sharing application in the world.

YouTube

youtube.com

Founded in February 2005, YouTube allows billions of people to discover, watch and share originally-created videos. YouTube provides a forum for people to connect, inform, and inspire others across the globe and acts as a distribution platform for original content creators and advertisers large and small.

Vimeo

vimeo.com

Vimeo is a respectful community of creative people who are passionate about sharing the videos they make. We provide the best tools and highest quality video in the universe. From the beginning, Vimeo was created by filmmakers and video creators who wanted to share their creative work, along with intimate personal moments of their everyday life. As time went on, like-minded people came to the site and built a community of positive, encouraging individuals with a wide range of video interests. We hope that you feel inspired to show us both your creative side as well as your friendly side.