Along with punny mugs and goofy bobbleheads, creative screensavers used to be a great way to let co-workers know just how fun you really were. They also protected clunky old computers from ending up with unreadable screens.

As HowStuffWorks explains, most early computer monitors contained a cathode-ray tube (CRT), which projected images onto the screen using phosphor. If a certain image was left on the screen for too long, however, the phosphor could leave an imprint of it on the glass—a phenomenon known as burn-in. A single imprint might not ruin your device, but enough burn-in could eventually make it difficult to see things on your screen. So programmers created moving image files, aptly named screensavers, that would automatically jump into action whenever your screen was idle for too long. Over time, cathode-ray tubes were replaced by liquid crystal displays (LCDs). Not only are LCD monitors smaller, lighter, and more energy-efficient, they also run without phosphor—so you never have to worry about burn-in.

While screensavers don’t actually save very many screens these days, they’re just as fun as they used to be. In fact, they might even be more fun, since graphics are more complex and the internet has many more options to choose from. Entertainment value is one of a few key reasons why screensavers have stuck around for so long. Another is cybersecurity. Some modern screensavers make you enter a password to regain access to your computer, thus preventing anyone from stealing your information while you’re on a coffee break. Certain companies even require the use of screensavers for this reason.

For other companies, screensavers function as a means of branding or even communication. If every employee in the building has the same screensaver, it creates a sense of identity, which can also be good for clients to see when they visit. Corporate screensavers can even be updated with important notices, event reminders, and other relevant information.

Feeling nostalgic for the classic screensavers of the CRT era? Here are 10 that you can relive on YouTube.

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