Top 10 Most Popular Social Networking Sites 

1. Facebook:

    Estimated Unique Monthly Visitors : 900,000,000

     To access Facebook.com, you must create an account on the site which is free.Facebook's terms of use state that members must be at least 13 years old with valid email ID’s. After updating you're details, your Facebook profile is generated.

2. Twitter:

       Estimated Unique Monthly Visitors: 310,000,000   

     Twitter is a very simple service that is rapidly becoming one of the most talked-about social networking service providers. When you have a Twitter account, you can use the service to post and receive messages to a network of contacts, as opposed to send bulk email messages.

3. LinkedIn:

     Estimated Unique Monthly Visitors: 255,000,000

 LinkedIn is an online social network for business professionals, which is designed specifically for professional networking, to help them find a job, discover sales leads, connect with potential business partners. Unlike most of the other social networks, LinkedIn does not focus on making friends or sharing media like photos, videos and music.

   

4. Pinterest:

  

        Estimated Unique Monthly Visitors: 250,000,000

Pinterest is a free website, which requires registration to use. Users can upload, save, sort, and manage images—known as pins—and other media content (e.g., videos and images) through collections known as pinboards. Pinterest acts as a personalized media platform. Users can browse the content of others on the main page. Users can then save individual pins to one of their own boards using the "Pin It" button, with Pinboards typically organized by a central topic or theme

5. Google Plus+:

      

         Estimated Unique Monthly Visitors: 120,000,000

There are currently 540 million monthly active users across Google Properties and 300 Million active in the Google + Stream.Google+ user base is roughly 60% male and 25% female as of November 2013. The remainder are "Other" or unknown. Early adopters of Google+ in mid-2011 were mostly male (71.24%), and the dominant age bracket (35%) was between 25 and 34. An August 2011 survey estimated that 13% of U.S. adults have joined Google+; it was projected to have 22% of U.S. adults in a year

  

6. Tumblr:

     Estimated Unique Monthly Visitors: 110,000,000

The service allows users to post multimedia and other content to a short-form blog. Users can follow other users' blogs, as well as make their blogs private. Much of the website's features are accessed from the "dashboard" interface, where the option to post content and posts of followed blogs appear.

7.Instagram :

     

       Estimated Unique Monthly Visitors: 100,000,000

Instagram is an online mobile photo-sharing, video-sharing and social networking service that enables its users to take pictures and videos, and share them on a variety of social networking platforms, such as Facebook, Twitter, Tumblr and Flickr. A distinctive feature is that it confines photos to a square shape, similar to Kodak Instamatic and Polaroid images, in contrast to the 4:3 aspect ratio typically used by mobile device cameras. Users can also apply digital filters to their images. The maximum duration for Instagram videos is 15 seconds.

8.Flickr:

    

      Estimated Unique Monthly Visitors: 65,000,000

 It is an image hosting and video hosting website, and web services suite that was created by ludicorp in 2004 and acquired by yahoo in 2005. In addition to being a popular website for users to share and embed personal photographs, and effectively an online community, the service is widely used by photo researchers and by bloggers to host images that they embed in blogs and social media.

9.vine:

      Estimated Unique Monthly Visitors: 42,000,000

Vine is a short-form video sharing service.it was acquired by micro blogging website Twitter in October 2012, just prior to its official launch. The service allows users to record and edit five to six-second long looping video clips, and revine. Revine is where users can share other peoples posts with followers.

10.Meetup:

       Estimated Unique Monthly Visitors:  40,00,000

Meetup is an online social networking portal that facilitates offline group meetings in various localities around the world. It makes it easy for anyone to organize a local group or find one of the thousands already meeting up face-to-face. More than 2,000 groups get together in local communities each day, each one with the goal of improving themselves or their communities.