If you could only say one word to someone who's sad, what word would you select?

That very question might be something Facebook is puzzling over. 

The social network is working on something that's not quite a "dislike" button, CEO Mark Zuckerberg said during a Q&A at Facebook's headquarters on Tuesday. "What [users] really want is an ability to express empathy," Zuckerberg said, according to the Wall Street Journal. "If you're expressing something sad...it may not feel comfortable to 'like' that post, but your friends and people want to be able to express that they understand."

Zuckerberg added that it was a surprisingly complicated task to build the button. One reason might be because Facebook doesn't want the button to be available as an option for every post. Rather, the company wants to limit use of the button--whatever it's called--to expressing sympathy when someone posts something upsetting, notes the Journal

Reading between these lines, I wonder if the problem is nuance. Not all upsetting situations are the same. The condolence or empathy or sympathy you wish to express for a friend who's lost a parent or pet is different from the one you'd want to express if someone shares an article about a crime or crisis. 

In the same way you'd bring different flowers or send different cards depending on the somber occasion, you'd also select different words or tones. Consider Facebook's challenge as a thought exercise: If you had to give this button a name, what would you call it? "Condolences" comes to mind, but it implies an emotional loss.

Maybe a five-word button--"my thoughts are with you"--would do the trick. But wouldn't that be more like a card than a button? Here's another possibility: That Facebook is avoiding language altogether. Perhaps the button will provide a choice of somber emojis. 

What's fascinating about this choice is how it will play out over the long term. When companies select the right word for the right function--as Facebook did with "like" at its inception--users become so comfortable with it, they almost forget it was a choice in the first place. When was the last time you considered the word "desktop" in a non-computer context? Yet the "desktop" metaphor was a conscious choice Xerox PARC came up with in 1970. 

Zuckerberg placed no timetable on when Facebook's new button would be ready. But whether the company chooses a word, an emoji, or some combination thereof, the ultimate test of will be if future users forget the company ever made one.