Man holding up paper that reads "You should know this"
Gustavo Frazao/

You might have seen the acronym “YSK” online before, often followed by facts and information. Not sure what it’s supposed to mean? Here’s what it stands for and why you should know about it.

You Should Know

YSK stands for “You Should Know.” It’s used on internet forums and chatting apps to let someone know about a useful fact or piece of information, especially if it’s something you recently learned about. For example, if someone messages you, “YSK that the game sale is ending tomorrow,” then that person is trying to give you a heads-up so you don’t miss out on a deal.

In this use case, YSK has some similarities with the acronym TIL or “Today, I Learned.” However, unlike TIL, YSK implies that this piece of information is useful to know, whether to you or to a large group of people. On the other hand, TIL is used for more educational purposes, such as sharing interesting but ultimately useless facts with a public audience.

Alternatively, it can also be used to convey that you should already be aware of a certain piece of information. For example, if you forgot to bring a pen to school, your classmate might tell you, “YSK that we have an important test today.” This implies that this is common knowledge, and your lack of awareness might cause problems.

The History of YSK

Much like other internet acronyms, YSK likely originated on internet forums and online chat groups as a way to shorten a common phrase. The first definition of YSK on Urban Dictionary dates back to 2009, and reads “you should know.”

Since then, the use of YSK has grown, especially since it became popular on Reddit. The acronym is a common sight on Twitter and other social media platforms as well.

Must-Know Information

You Should Know Reddit Header

The most common use of YSK is as a way to share useful or must-know information with an audience. This is especially prominent on the Reddit community r/YouShouldKnow, which has over 3 million users. Every day, members submit posts that start with “YSK,” followed by pieces of information that they consider essential.

These can be anything from warnings about sneaky marketing campaigns to obscure facts about personal health. Many users also share useful free resources that are underutilized. The subreddit is a great public resource for anyone, especially because Reddit’s system automatically moves the most popular or upvoted pieces of information to the top of the page.

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When used in this way, YSK takes on a similar meaning to PSA or “public service announcement.” Both convey that a piece of information is important for as many people to know about as possible, as it may be crucial for their safety, wellbeing, or day-to-day life.

Woman taking notes on paper next to a laptop

Even in smaller groups, the use is very similar. For example, if you’re in a group chat with a bunch of your close friends, you might message them “YSK” to share something useful. Perhaps you’re talking about a new kitchen tool that you just discovered or a website with useful information about tech.

You Should Already Know

There’s another way to use YSK. Instead of using it to share information with someone else, you can use it to imply that someone should already know about what you’re saying.

Depending on the context, this can be kind or be harsh. For example, if your partner tells you, “YSK I love you,” they’re saying it to remind you that you are loved, which is a sweet sentiment. On the other hand, if someone tells you “YSK how to do this” after you fail at doing a task, then they’re telling you that the task is fairly simple and you should not mess it up.

How to Use YSK

In order to use YSK, simply substitute the acronym for when you want to type out “you should know.” Unlike some other internet slang terms, YSK is rarely spoken out loud. Most people say “you should know” or “you should already know” instead.

Here are a few ways you can use YSK in your next text:

  • “You’re already 29. YSK how to do your own taxes.”
  • “YSK that the highway is closed over the weekend.”
  • “YSK that you’re beautiful just the way you are.”
  • “YSK that How-To Geek is a great place to get helpful tips about tech.”

If you think YSK more internet acronyms, check out our pieces on W/E, TBH, and RN. You’ll know how to type like a digital native in no time.

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Profile Photo for Vann Vicente Vann Vicente
Vann Vicente has been a technology writer for four years, with a focus on explainers geared towards average consumers. He also works as a digital marketer for a regional e-commerce website. He's invested in internet culture, social media, and how people interact with the web.
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