UNIT 1 THE WEB

4)SHARING INFORMATION
We can define social networks as virtual environments for communication,interaction and the sharing of resources.They can be divided into two groups:horizontal or general social networks and vertical or thematic social networks.
4.1)Horizontal Social Networks
The users of horizontal networks from communities who have diverse interests and a wide variety of reseasons for using the application.The most popular examples of horizontal networks are:

• Facebook:This application allows groups of friends to publish both public and private messages with text,links,news,photos and videos.They may also share information about how they are feeling or what they are doing at any particular moment.Facebook can also be used by compaines to give information about their activities,advertise products and communicate more directly with customers.
• Twitter:This social network has some unusual features.Users publish short texts messages(tweets) with no more than 140 characters,wich is called microblogging.On Twitter,the relationships between users are not always bidirectiona.For example,you can follow the tweets of another user,but that person might not follow you.One of the most interesting functions is using hashtags(#) to follow interesting events or topics.
• Google+:This social network allows users to create circles of friends in order to share information.They can share photos and form public or private communities.In addition,an instant message application called Hangouts lets users connect with each other for audio conversations and videoconferences.
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4.2)Vertical Social Networks

The users of a vertical networks from communities who have similar reasons for using the application.These reasons,which can be personal or professional,may include:

• Sharing professional information:LinkedIn is the most popular network for all kinds of professionals.
• Sharing general information:With FriendFeed,people can create private groups to share information about projects,organise and excahnge photos or experiences with their friends.
• Sharing photos:Instagram,Flickr,Pinterest and Picassa are popular.
• Sharing videos:Youtube,Dailymotion and Vimeo are common examples.
• Live streaming:Skipe,Twitch.tv,Livestream and Upstream.tv are often used.
• There are many other services related to sports,cinema,books and other topics.