Egyptian Romanized Arabic (ERA) is the Egyptian variety of the writing that arose when Arabic speakers joined the domain of computer-mediated communication. At a time when almost all text on the Web was in English, and only basic Roman letters were supported, they had to use the Roman script to communicate with each other in Arabic. Based on data from more than one hundred users, I hoped to draw a picture of how ERA is written in general. As there is no official orthography or spelling rules in ERA, the basis for my analysis is that they would attempt to write as they speak, from phoneme to grapheme, but perhaps with interference from Arabic orthography. In addition to finding out to what degree Arabic orthography influences on the writing, I wanted to examine whether ERA is a stable writing system with emerging norms. I claim that ERA primarily is a transcription from the users' speech to writing, but it certainly seems to be influenced by Arabic orthography as well, although the degree of influence varies between different features. Additionally, it seems to be influenced by ad hoc transcription, the non-standardized transcription that is common on road signs and in general when Arabic names are written in the Roman script, and by English orthography. The writing systems is quite stable when it comes to representation of the consonant phonemes, but less so where the vowel phonemes are concerned.