Have you ever played Snake on a Nokia phone? Driven a car with a tape deck? Do you remember calling someone after they beep you on your pager? As “throwback” memes and nostalgic photos make the rounds on social media, internet users have been inventing new slang to describe their feelings about bygone eras.

On the internet, bittersweet memories are often captioned with “时代的眼泪 (shídài de yǎnlèi, tears of time),” a translation of a Japanese phrase for fading popularity. The buzzword compares the forgotten thing or person to tears, which dry quickly and leave no mark on the stream of time. For instance, a former pop star who returns to the limelight might evoke the outcry, “She was the goddess of my youth. What a pity! Once a household name, now a tear of time. (她是我童年女神呢!可惜了，曾经红极一时，现在却成了时代的眼泪。Tā shì wǒ tóngnián nǚshén ne! Kěxī le, céngjīng hóngjí yìshí, xiànzài què chéng le shídài de yǎnlèi.)”

Old things, though, can also become classics. 古早(gǔzǎo), a term in southern Fujianese dialect meaning “classic” or “retro,” has become synonymous with vintage trends that make a comeback. Guzao makeup (古早美妆 gǔzǎo měizhuāng ) is a fad for cosmetics made from natural products used in ancient times. A guzao series (古早剧 gǔzǎojù) is a formerly popular TV drama worth revisiting, and guzao-flavored food (古早味食物 gǔzǎowèi shíwù ) refers to traditional recipes that bring back customers’ childhood memories.

Yet some retro trends are really best left forgotten. The term “dark history (黑历史 hēilìshǐ)” refers to shameful past scandals and secrets that a person, usually a celebrity, wishes to hide—the equivalent of “skeletons in the closet.” It is a favorite phrase of “clickbait” headlines, which scream: “Here are the secrets that celebs most want to hide (明星最想销毁的黑历史在这儿！Míngxīng zuì xiǎng xiāohuǐ de hēilìshǐ zài zhèr)!” Some entertainers or their agents are even said to feed this line to the media as a publicity stunt.

Unfortunately for those who would rather bury their skeletons, “The internet remembers (互联网是有记忆的 Hùliánwǎng shì yǒu jìyì de).” This phrase points out the reality that photos, posts, and comments can almost never be erased once published on the web, and are available to anyone with a quick search.

In some cases, screenshots from the internet serve the cause of justice. Last October, during an acrimonious divorce between Li Guoqing and Yu Yu, billionaire cofounders of the e-commerce platform Dangdang, text messages dating as far back as nine years ago backed up Yu’s accusations about her husband’s extramarital affairs.

The internet’s long memory also powers the “human flesh search engine,” vigilantes who seek personal information to use against a criminal or moral offender, and online trolls: “The internet never forgets. She faked her college degree; she hardly deserves to be a star (互联网是有记忆的，她伪造过学历，根本不配当明星。Hùliánwǎng shì yǒu jìyì de, tā wěizào guo xuélì, gēnběn bú pèi dāng míngxīng. ),” they might exclaim about a hated celebrity.

So while it’s fun to post a throwback photo on Weibo once in a while, be careful what you share with the internet. Or just get a Polaroid camera—they’re retro, making a huge comeback, and you can always destroy the evidence.