As ridiculous as it sounds, Monday is celebrated as World Emoji Day.

That’s because July 17 is the day that appears on the iPhone emoji for “calendar.” The day was picked because it’s the birthday of Apple’s iCal product.

Emojis, those digital images people send each other by text and social media, reflect the changing nature of communication, both for individuals and for businesses. Think about it: We went from the phone to email. Then from email to text messages. Now, we’re going from actual language just to pictures.

Consider that the majority of Instagram users employ emojis in their posts, according to social media analytics blog quintly. About 76 percent of Americans said they used emoji in business communications, according to a survey cited by The Atlantic.

There are 2,666 official emojis in the Unicode Standard, as of May, that always work. Plus there are countless unofficial emojis introduced by companies, brands and even individual celebrities. Apple marked World Emoji Day by releasing final versions of a few new emojis that will be part of iOS 11, which comes out this fall. There’s a new “bearded person,” “breastfeeding” and a mushroom-cloud-exploding head, plus a zombie and some others.

There are other examples of corporations getting in on the emoji game:

Dominos now lets you order pizza by emoji.

Chevrolet put out a whole press release in emoji, inviting people to decode it.

Goldman Sachs tweeted completely in emoji to highlight a research report on millennials.

Twitter charges companies around $1 million a piece to get customized emojis on the platform. Customers include Coca Cola, Pepsi, Starbucks and Disney.

Snapchat spent $100 million on a company that turns your face into an emoji.

There’s a business reason behind all this: Academic research suggests there’s more user interaction when you use emojis.