To transcend cultures and languages, Facebook uses symbolic menu icons at the top of the page. The silhouette of two people shows where friend requests are managed. The chat bubbles represent inbox and instant messages, and the globe icon houses notifications. Just to the right of those symbols is a lock icon, representing privacy settings. The upside-down triangle is a drop-down menu of page settings.
The need for space-saving symbols has a lot to do with mobile consumption. As society consumes media in smaller and smaller formats, Web pages, like Facebook, must find ways to condense a website into a format that translates to a variety of devices.
While these symbols are used to save space in the design of the page, they are also implicated as a way to bridge the language barrier without having to translate the entire page. Just as the lower case "i" is used as the international symbol for information, symbols are frequently used to represent an idea without using words.
Not only does Facebook use symbols in its interface, but its social networking icon is also a symbol. Facebook's widely recognizable icon of a lower case "f" is so popular, it is nearly synonymous with social networking itself.