If you've ever scrolled though the comments on a celebrity's Instagram page, you've surely noticed that they all have one thing in common: thousand of users posting the letters "LB" without any explanation. Needless to say, the trend has left many scratching their heads.

So, what does "LB" in an Instagram comment actually mean?

The acronym stands for "like back," meaning a user will like one of your posts if you like one of theirs. The more likes you rack up on a photo, the more popular your account looks. Many Instagram users comment "LB" on a star's page instead of a friend's since a celebrity has millions of more followers than an ordinary user, meaning their comment has the potential to be seen by more accounts.

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Some people write "l4l" or "like4like," which means the same thing — if you help my page become more popular, I'll return the favor. The technique has caused plenty of Instagram fanatics to go overboard trying to gain more likes, spamming photos with dozens of "LB" comments — and Kylie Jenner, who receives millions of comments each day, asked her legions of fans back in 2012 to stop posting the phrase. Needless to say, no one listened.

Though the fad isn't dying out anytime soon, you can prevent followers from commenting in general, as Instagram gives you the option to turn off comments on any of your own photos. If you still want your followers to be able to comment, but you don't want to see "LB" on every post, you can instead just block the phrase — so if someone does write "LB," it won't show up for others to see.

In fact, Kim Kardashian used the trick after her feud with Taylor Swift blew up. Originally, Taylor haters began calling her a snake, and Kim was quick to jump in on the gag — but eventually, the "End Game" singer flipped the script and embraced the nickname, making snakes a theme in the artwork for her album Reputation. Soon enough, Swifties flooded Kim's Instagram with the snake emoji, and the reality star was so annoyed that she blocked the emoji from appearing in her comments.

Other popular phrases you'll probably come by on Instagram include "CB," meaning "comment back," or "FB," meaning "follow back." Basically, it's a simple (but annoying) way for Instagram users to increase their follower count and likes.