You are only allowed about 180 characters when sending a text message. So due to the limited space available this particular method of communication is known as a informal method of communication. A lot of people even shorten words which make it easier for them to say what they want. Due to text messaging being informal it has caused a lot of people to send funny text messages. They are usually one liners that will really make you laugh. Sometimes after you send a funny text message you will get a reply back that plays along with your original message.