Here is a list of top 16 social networking websites that you may to want to explore...
Quora - www.quora.com
Quora is a question-and-answer website where questions are created, answered, edited and organized by its community of users.
Facebook - https://www.facebook.com/
Connect with friends and the world around you on Facebook. See photos, share updates.
Twitter - https://twitter.com/
Enables users to send and read short 140-character messages called "tweets". Registered users can read and post tweets, but unregistered users can only read them.
LinkedIn - https://www.linkedin.com/
Business-oriented social networking service. Founded in December 2002 and launched on May 5, 2003, it is mainly used for professional networking.
Pinterest - https://www.pinterest.com
A content sharing service that allows members to "pin" images, videos and other objects to their pinboard.
Google+ is a place to connect with friends and family, and explore all of your interests. Share photos, send messages, and stay in touch with the people
Tumblr - https://www.tumblr.com/
Tumblr is 235 million different blogs, filled with literally whatever.
Instagram - https://instagram.com/
Take a picture or video, choose a filter to transform its look and feel, then post to Instagram/ any other social networking site
Flickr - https://www.flickr.com/
Image and Video hosting website
VK - vk.com
VK is the largest European social network with more than a 100 million active users.
Vine - https://vine.co/
Vine makes video fun. You can watch, create and share short looping videos -- anytime, anywhere.
Meetup - http://www.meetup.com/
neighbors getting together to learn something, do something, share something…
Tagged - http://www.tagged.com/
Tagged makes it easy to meet and socialize with new people through games, shared interests, friend suggestions, browsing profiles, and much more.
Ask.fm - http://ask.fm/
Ask.fm is a global social networking site where users create profiles and can send each other questions, with the option of doing so anonymously.
MeetMe - http://www.meetme.com/
MeetMe helps you find new people nearby who share your interests and want to chat now! It's fun, friendly, and free!
ClassMates - http://www.classmates.com/
Find High School Alumni, Yearbooks and Reunions