"Facebook, for example, encourages phatic communication through sociable add-ons like 'vampire bites', 'zombies', 'hot potatoes' and automating messages encouraging participation between friends in quizzes, film taste reviews and the like. Furthermore, Facebook's new 'beacon' technology creates an environment where one's online purchases and interests get relayed to one's network of friends through automated communication. Twitter encourages phatic communication through the imposed limits of the medium itself. The 160 character limit for messages creates brevity in communication. The lack of a private messaging facility, promotes generic 'announcements' over dialogue or targeted conversation. "
(Vincent Miller, 2008, p.398)
 For example, a typical automated message such as ''Mr X' has challenged you to a movie quiz' suggests a personal invitation to compete. However, it is usually the case that if 'Mr X' has participated in a movie quiz, you will, by default, be automatically 'challenged' to the quiz, by virtue of being friends with 'Mr X'.
Miller, V. (2008). "New Media, Networking and Phatic Culture." Convergence: The International Journal of Research into New Media Technologies 14(4): 387–400.
"To understand how federated social networking would be an improvement, we should understand how online social networking essentially works today. Right now, when you sign up for Facebook, you get a Facebook profile, which is a collection of data about you that lives on Facebook's servers. You can add words and pictures to your Facebook profile, and your Facebook profile can have a variety of relationships – it can be friends with other Facebook profiles, it can be a 'fan' of another Facebook page, or 'like' a web page containing a Facebook widget. Crucially, if you want to interact meaningfully with anyone else's Facebook profile or any application offered on the Facebook platform, you have to sign up with Facebook and conduct your online social networking on Facebook's servers, and according to Facebook's rules and preferences. (You can replace 'Facebook' with 'Orkut,' 'LinkedIn,' 'Twitter,' and essentially tell the same story.)
We've all watched the dark side of this arrangement unfold, building a sad catalog of the consequences of turning over data to a social networking company. The social networking company might cause you to overshare information that you don't want shared, or might disclose your information to advertisers or the government, harming your privacy. And conversely, the company may force you to undershare by deleting your profile, or censoring information that you want to see make it out into the world, ultimately curbing your freedom of expression online. And because the company may do this, governments might attempt to require them to do it, sometimes even without asking or informing the end–user.
How will federated social networks be different? The differences begin with the code behind online social networking. The computer code that gives you a Facebook profile is built in a closed way – it's proprietary and kept relatively secret by Facebook, so you have to go through Facebook to create, maintain, and interact with Facebook profiles or applications.
But federated social network developers are doing two things differently in order to build a new ecosystem. First, the leading federated social networking software is open–source: that means that anybody can download the source code, and use it to create and maintain social networking profiles for themselves and others. Second, the developers are simultaneously collaborating on a new common language, presumably seeking an environment where most or even all federated social networking profiles can talk to one another.
What will that likely mean in practice? To join a federated social network, you'll be able to choose from an array of 'profile providers,' just like you can choose an email provider. You will even be able to set up your own server and provide your social networking profile yourself. And in a federated social network, any profile can talk to another profile – even if it's on a different server.
Imagine the Web as an open sea. To use Facebook, you have to immigrate to Facebook Island and get a Facebook House, in a land with a single ruler. But the distributed social networks being developed now will allow you to choose from many islands, connected to one another by bridges, and you can even have the option of building your own island and your own bridges."
(Richard Esguerra, 21 March 21 2011, Electronic Frontier Foundation)
"Twitter has launched Vine, an addition to the social network that allows users to embed six second videos within their tweets. ... Videos posted on Vine are on an infinite loop – in a manner similar to animated gifs, an image format that has been popular since the very early days of the internet."
(BBC News, 24 January 2013)
(Mark Otto, 17 January 2012, A List Apart)