The Facebook logo was designed by Joe Kral and Cuban Coucil. It is a judicious modification of Eric Olson’s Klavika, with tighter spacing, some wider lettershapes, and a taming of Klavika’s very distinctive ‘k’. In the same way that Facebook represents the culture and technology of a decade, Klavika does the same for typeface design — well crafted but blatantly simple, monolinear, square, nearly devoid of any calligraphic ancestry.
“The Social Network” film, in turn, uses Klavika (along with Futura) for its logo and promotional graphics. It’s an expected and obvious choice, but it works well. It says “Facebook” without having to say it outright.