Communication is increasingly taking place through written messaging using online and mobile platforms such as email, instant messaging and text messaging. A number of scholars have considered whether these texts reflect spoken or written language, though less is known about the role of punctuation. In fact, it is commonly assumed that punctuation on such platforms is either random or absent. This study explores the nature of punctuation (including emoticons) in electronically-mediated communication by analyzing sets of focus group data from adolescents discussing text messaging and by assessing a corpus of text messages sent by university students. Some usage patterns are gender-based. More generally, there is evidence that young people are developing coherent strategies for how such marks should be used in messages created on new digital media. (Contains 3 tables and 8 footnotes.)