While emojis look odd in formal writing - think important emails, and online articles like this one - they are used by almost everyone in text messages and on social media.
However despite their widespread use, the study of emoji use is in its infancy.
So, in an article recently published on Trends in Cognitive Sciences, a group of international researchers from Australia and the UK are calling on other researchers to study our use of emojis.
"Emojis provide us with an insight into human behaviour in the digital age," Australian Catholic University researcher Dr Stephanie Malone said.
"As emoji research is just in its infancy at the moment, there are lots of directions that this research could take and I look forward to seeing what comes of it."
Dr Malone, who has already done some research into emojis with counterparts in the UK, said their research has turned up interesting findings - including the fact that people are "discerning" in their emoji use.
"Our research shows that despite people being aware of how useful emojis can be, they are aware that using emojis in some contexts - for example, email - may be less appropriate," she said.
She said we use facial expressions in face-to-face conversation to help convey our meaning, and the researchers found we use emojis in written text to do the same thing.
"Using emojis helps to clarify the intended message," Dr Malone said.
She said their research also found people can form opinions of others "based on their emoji usage."
"Specifically, we found that people are able to judge accurately the user's level of openness to experience and extraversion on the basis of their emoji usage."
Studying the use of emojis is not without setbacks, however.
"One challenge is that a lot of emoji use happens in a private communication," Dr Malone said.
However the "vast array" of public blogs, Facebook comments and websites that use emojis mean they can be studied in "a variety of contexts".
"It is also possible to replicate these more 'private' forms of communication by setting up an instant messaging conversation between two people (with their consent) and monitoring their spontaneous use of emoticons," she said.
Dr Malone, a prolific user of emojis herself, said there are "many directions" the study of emojis could take.
"One possibility is to look at the use of emojis as a support for children with communication difficulties, to examine whether the inclusion of emojis can help them in understanding the meaning of written text," she said.
"It could be interesting to examine if the brain processes emojis in the same way as it does human facial expression."