I can’t believe how many companies make this mistake. Every video impression counts when you’re building your user base, and closed captions help you reach a wider audience.

There are three main segments of the market that are assisted by CC:

People who can’t turn the sound on

There’s plenty of reasons why someone just can’t turn the sound on. Perhaps they’re on a train and forgot their headphones. Maybe they’re at the office or at school. Maybe their favourite song is playing in Spotify and they don’t feel like pausing the music. They might bookmark your video for later, but far more likely they’ll just forget about it.

With captions, the viewer can enjoy the video without sound. If it’s really rad, maybe they’ll even go locate some speakers so they can hear the funny parts, and share it with whoever’s nearby.

The Deaf

Deaf people have more to gain than the average person by being tech savvy. Until the last couple of decades, a deaf person was essentially shut off from society. Unable to communicate with the hearing, they could only associate with people who could sign to them – if they were even allowed to sign.

But with text messaging, email, cochlear implants, and yes, closed captions, deaf people more able than ever to take advantage of the best parts of life on earth in the 21st century. They’re likely to be early adopters, and also likely to adapt your application in ways you never imagined. There are a lot of them on the internet, and having captions on your video is a great way to get them interested in your product.

Non-native English speakers

Surprisingly, the majority of the planet does not speak English as their first language. You’re probably aware, though, that most well educated people learn it as a second language since it’s the language of commerce. That means that non-native English speakers are a potentially huge market, (depending what your product is), and it’s worthwhile to cater to them.

Closed captions are very useful when someone doesn’t quite know what a word means – they can see it in the captions and look it up. It’s a heck of a lot easier than trying to figure out the bizarre English spelling of a word they’re not familiar with, and googling their best guess.

Closed captions are worth the effort – and for the average sub-five-minute demo video, it’s not even a lot of effort. Youtube provides an easy way to generate captions, then you can edit the generated file to make it perfect. If captions aren’t supported, you can always hardcode them and provide a link to the captioned version of the video.

Some companies are getting it right.

Circuit Lab (YC 2013) was the only YCombinator startup I could find that had good captions available. Please let me know if your company has captions in its demo video, I’ll link to you. TED.com also has captions available in almost every video, in dozens of languages.

But in a search of dozens of Ycombinator companies and other internet startups, Kickstarters, and so on, I found very few videos with captions. It’s not hard or expensive to do. Do it.