The other reason people are upset about the 'hijacker selfie'
OK, let's start at the beginning. What is a selfie?
The Oxford English Dictionary defines it as "a photograph that one has taken of oneself, typically one taken with a smartphone or webcam and uploaded to a social media website."
So that's pretty clear - the picture has to be taken by a person who actually appears in it.
That brings us to the photo of the moment - the image of grinning Ben Innes next to the alleged EgyptAir hijacker Seif al-Din Mustafa.
Innes, himself, said of the snap: "It has to be the best selfie ever!"
Many were understandably astonished that Innes had asked for a picture with a man who was holding him, and others, hostage wearing what was then thought to be a suicide bomber belt, but which later turned out to be a fake.
But that wasn't the only reason people got exercised about the photo:
More than 45,000 people tweeted about the picture. Many including several comedians, went with the selfie line:
Others were steadfast in their opposition:
The BBC avoided the word "selfie" in the headline to its original story about the photo. But many other publications, to the annoyance of some, did drop the s-bomb in big type.
And the word even earned a rebuke from Innes' mother who (in addition to expressing some concern about her son's safety) said: "All we can say is that the picture is clearly not a selfie as everyone has been describing it."
Follow BBC Trending on Facebook
Join the conversation on this and other stories here.
To further drive the point home phone footage, apparently filmed by another hostage, has now emerged of the non-selfie being taken by the one of the cabin staff on the hijacked plane.
And of course, there have been plenty of jokes, and laments at the state of the world (and the English language):
Next story: Brazil's political troubles play out online
Brazilians are cataloguing violent incidents stemming from the country's political divisions. READ MORE