Are we going back to hieroglyphics? Not exactly hieroglyphics, but more like picture writing. Because hieroglyphics are about phonemes, or sounds: just like the sound of the word 'water' will give you the picture of 'water' in your mind. In social media posts, we are using what we call emoticons. In India, there is an unregulated interpretation of emoticons. I've read that in one occasion in Canada, an emoticon was interpreted by a judge as acquiescing to a business agreement, and a respondent had to pay damages for infringement of a purported business deal as the respondent had posted an emoticon (showing thumbs up) in response to a proposed business plan.
But emoticons can be interpreted differently in different cultures. A 'thumbs up' 👍would be agreement in one culture, and 'angutha dikhaana' in another. Now, 'angutha dikhaana' in Hindi is an idiom that means mocking someone. Similarly, the emoticon of owl would be to show wisdom in one culture, and 'Ullu' in another. 'Ullu' in Hindi is owl, but is also idiomatically used to describe a fool.
Another thing we find today in social media posts - and lately in formal writing - is emphasis given to a sentence by repeating the punctuation mark at the end of the sentence. For example, if you want to shout out how important your question is just print a dozen question marks after your sentence. If you want to show how important or profound your sentence is just add a few exclamation marks after your sentence. In any case, interrobang (!?) is being used like loose change in social media posts these days. And, we also have repetition of a vowel purportedly for emphasis: for example, loooong for very long, etc.
Many social media headings are full of hieroglyphics (read emoticons): some with flowers, followed by bouquets, followed by hearts, followed by what we call smileys. At least, I'm unable to decipher the meaning of such headings.
How will the future generations read such hieroglyphics? Perhaps they will take help of the Sumerians or the millennial generations' limited vocabulary.