Recently, there was a blog post which described a browser security feature as "like a seat-belt that snaps when you crash."
This wasn’t a particularly noteworthy event because similes are pretty common in our field. Almost everyone likes similes because they enable the simplification of highly technical topics into easily-conceptualized terms that anyone can understand. Similes are like JPEGs – they distill a big, complicated, intricate picture into a smaller (but still evocative) picture that bears some amount of resemblance to the original truth.
In our headline-driven culture, where subtlety and nuance don't draw the clicks that a quick witticism can bring, a great simile will spread across the web like pollen on a spring morning.
Of course, the downside1 is that, like JPEGs, the compression is lossy. Important information can be obliterated in the conversion process. Technical experts might observe the loss, but an everyday consumer may not detect the difference. In some cases, that’s fine, but in others it really isn’t.
The problem with the simile in that recent blog post is that the information loss is unnecessarily high. The topic is complex, but that doesn't mean we can't use a simile—we just need to think a little harder.
Two more accurate similes immediately leap to mind. We could describe the security feature as
"Like a bicycle helmet that won’t prevent drowning if your boat sinks."
Or we could say it’s
"Like a flak jacket that can’t protect the lungs from chemical weapons."
Both of these are accurate statements that more closely reflect reality. They convey to the everyday person the nuance that the feature doesn't protect against all attacks—specifically, not those that it's not designed to protect against.
It's absolutely fair to wonder "Hey, why not develop a bike helmet that also acts as a life preserver?" Or, "Why not replace flak-jackets with MechWarrior-style exoskeletons that protect against a full spectrum of attacks?" These are legitimate questions, to be sure, but neither mistakenly suggests that bike helmets or flak jackets don't have their place in the world as it exists today.
The next time you hear a great simile, think carefully about what information its originator might have left out, and what motivations they may have had when crafting it.
1 Of course, if you're the one trying to convince someone to buy or adopt something, the loss of information that contradicts your point of view is considered an upside, not a downside.