Facebook is an American for-profit corporation and an online social media and social networking service based in Menlo Park, California. Twitter is an online news and social networking service where users post and interact with messages, "tweets," restricted to 140 characters. Registered users can post tweets, but those who are unregistered can only read them. Google Plus is an interest-based social network that is owned and operated by Google . The service, Google's fourth foray into social networking, experienced strong growth in its initial years, although usage statistics have varied, depending on how the service is defined. Instagram lets registered users upload photos or videos to the service. Users can apply various digital filters to their images, and add locations through geotags . They can add hashtags to their posts, linking the photos up to other content on Instagram featuring the same subject or overall topic. Pinterest is a we