Communicating in plain text can be really tough; it just doesn't allow the subtlety, nuance and level of emotion that humans need to understand conversations properly. If you struggle with it, the Sound-Word Index might be able to help you out.
A pair of Royal College of Art graduates, Blanche de Lasa and Stina Gromark, are developing a crowd-sourced reference library which attempts to allocate meaning to various letter repetitions and onomatopoeia used on the internet. Think of it as a dictionary for digital communication allowing you to decode the subtlest of differences in what your friends are saying, in order to reply appropriately.
It makes some neat use of typography and emoticons to help you get to grips with the text, but the most amusing aspect is the fact that the pair are also trying to represent how certain strings of text—like "!!!"—might sound in real life. But what differences does it make if there are four bangs, hmmm? [Sound-Word Index via The Verge]