Best android app you must know about -Facebook 

                          Facebook 

The Facebook website was launched by Mark Zuckerberg Facebook may be accessed by a large range of desktops, laptops, tablet computers, and smartphones over the Internet and mobile networks. After registering to use the site users can create a user profile indicating their name, occupation, schools so on. Users can add other users as friends exchange messages, post status updates and photos, share videos and links, use various software applications and receive notifications when others update their profiles or make posts. Additionally users may join common-interest user groups organized by workplace, school, hobbies or other topics, and categorize their friends into lists such as People From Work or Close Friends. In groups Additionally users can complain about or block unpleasant people.