Nope, you’re not going crazy — Facebook has changed its font ever-so-slightly. But unless you’re a graphic design fiend, you probably haven’t noticed exactly how it’s different.
As Mashable reports, Facebook is testing a new, thinner font for some users. Called “Geneva,” it’s thinner and lighter than the Helvetica it’s replacing. The difference is incredibly subtle, but the overall effect is a lighter, more modern looking block of text. Remember when Apple moved from Helvetica to Helvetica Neue? It’s roughly the same kind of feel, although Facebook’s font isn’t as dramatically thin as Helvetica Neue.
At the moment, it seems to just be a trial, as only some desktop users are seeing the new font. It hasn’t rolled out to any mobile users yet (or at least, not that we’ve heard).
The font change is most visible on the uppercase G. On Helvetica, there’s a downwards kicker that vanishes on the new font. The same thing also happens on the lowercase a.
If you have strong enough feelings about fonts to hate the change, I wouldn’t worry just yet: Facebook has a long history of beta-testing new features with a small audience before rolling them out more widely, so Helvetica isn’t on its deathbed quite yet.