The Facebook app is, of course, the mobile version of the world’s largest social network site, and one of the more complex apps in this study. Both Facebook and its iOS app has changed many times. Here, I am analyzing version 5.0.
Facebook has two kinds of basic nodes: Persons and «pages». «Pages» are for members who are not real persons, such as companies, organizations, and the like, and for celebrities and other people who want a public presence on Facebook. When a user chooses to subscribe to another person’s messages while allowing the other person to subscribe to hers, they become «friends». To subcribe to a page is called to «like» the page.
Users are invited to «share», that is, to publish, using three buttons next to the top of the app’s main screen. «Status» allows to write a short message with the on-screen keyboard and publish it. «picture» lets the user take a picture with the camera on the device and upload it, or, alternatively, upload a picture from the camera’s memory. «Check in» uses the device’s GPS and Wi-Fi receptors to calculate the device’s location, and uploads it to Facebook. A list of registered placenames nearby is displayed, so the user can select one of them, and upload the name too. Statuses, pictures, and check-in can be combined.
Users can also form «groups», subscribing to a page where they can post messages to all the group members, and they can invite others to «events», which are registered with a time, a place, a description, and a list of invited guests. All guests will be members of a new group for the event.
When a user publishes a status, a picture, or a check-in, it becomes what we here will call an occurrence that can be read by the user’s «friends». Most of the main screen is thus occurrences from a selection of the user’s friends and «liked» «pages». This is called the «news feed». Each occurrence in the news feed contains a link to a separate screen for the occurrence, and a link to the user who posted it. Other users can comment on the occurrence by pressing «comment», which brings up a on-screen keyboard, or pressing «like», registering a thumbs-up. The comments and the likes count is displayed on the occurrence’s screen. Every time a person comments on or likes something, it becomes a new occurrence that also gets reported in other users’ news feeds.
If you want to delete your occurrence, you can do a left swipe on it, which will open an action sheet asking if you want to hide the occurrence or delete it altogether.
If a user has written an URI in her status, a link to the Web page is created, together with a thumbnail image. Pressing the link will open the Web page within the Facebook app. A button at the bottom allows two actions: to open the page in the device’s Safari browser, or to «share» the page, that is, to post a link to it on your timeline and to your friends’ News Feeds.
Pressing the link to the user who posted the occurrence brings up that user’s «timeline», which displays a selection of all the public information Facebook has on her or him: Basic information, images, list of friends, page likes, and occurrences.
The button with left-pointing arrow at the top will bring the News Feed back. The button with the «share» symbol brings up an action sheet with five options: Block (from the News Feed), Poke (which will send her or him the message that you «poked», nothing more), Call, which will use the phone to call her or him, and Text, which will open the Message app to create an SMS message.
On the very top of the news feed is a row of five buttons. The center three are notifications. When pressed, they display a speech-bubble-formed overlay showing new friend requests from other users, messages from other users, or a list of other people who have liked or commented on your occurrences.
The top right button allows the user to filter what’s on her news feed. There are two settings: «Top stories» will show the most commented and liked post from the friends the user has had most interactions with on Facebook, while «Recent posts» will sort out older posts, giving room for more of the recent occurrences in the user’s network.
The top left button causes the main screen to slide to the right, revealing a main menu underneath.
On top is a link to one’s own timeline, and below, links to the News Feed, messages (an e-mail-like service for private messages between you and your friends), a list of friends who have checked in near your last check-in, a list of events you are invited to, and a list of all your friends.
Then follows links to all your «applications», the groups you are member of, the categories you have sorted your friends into, and at the very bottom a link to the help menu, containing a large number of help pages, and links to settings and terms of service.
Very little of all this information is stored in the app itself, which takes up 7.3 Megabytes of memory. The app is a terminal into the Facebook service, giving access to most, but not all, of Facebook’s features.
Compared with the Web version, the most obvious difference is that the entire right column on Facebook.com is missing from the app. This includes the «Ticker», which shows all your friend’s occurences in real time, birthday reminders, and advertisements.
The Web version also allows a few actions that are not available in the app. There is a «Share» link below every occurrence, allowing the user to re-post the status, image, video, to his or her timeline and friends. You may not only delete your own posts, you can also edit them, and you can mark some of them as «highlighted», which means that they will stay longer on your timeline. Stories in the News Feed are stamped with time and place, and a tiny pop-up menu allows you to «follow» the post, hide it from your News Feed, or report it as spam.
If you visit facebook with the Safari browser on the iPhone, however, you are redirected to m.facebook.com, which in Safari looks almost entirely like the Facebook app, and offers exactly the same functionality (if your browser allows access to the camera. The current version of Safari on iPhone does not).
To analyze the Facebook app as an app alone will thus only show parts of the Facebook phenomenon. Rather than an app, it is a terminal among several into the Facebook service. A mobile app allows you to take Facebook with you, and record photos, videos and statuses as you are moving around away from you computer. It also allows you to use Facebook to kill time while commuting, waiting, and being away from the computer desk. Thus, it expands the reach of the Facebook service, but it does not radically alter the experience.
This is very much the point Tim O’Reilly brought forward in a comment to Chris Anderson’s much discussed Wired article ‘The Web is Dead’:
´[W]eb sites’ like Google, but also now Facebook, Twitter, Amazon, PayPal, LinkedIn and many others, have been quietly building those enormous data back ends that drive their web sites, but more importantly, also drive a vast array of web services. Google maps in the browser is still Google maps, with all the intelligence, all the deep data layers, that make it a success on either front-end. What the mobile ecosystems of today have done is to unmask the reality that it’s the back end that matters. […] It’s easy to focus on the apps themselves, down on the phone, and to forget just how many of the key apps are the same networked apps that we see on the web, just with a different front end.
 What we here call an occurrence called an edge among Facebook’s developers, as it is represented as a vector in a polynom in the algorithm that sorts the News Feed. See <http://www.livestream.com/f8techniques/video?clipId=pla_5219ce25-53c6-402d-8eff-f3f8f7a5b510>