Emoticons play an important role in digital written communication: they can serve as markers either of emotions or familiarity, and they can intensify or downgrade the pragmatic force of a text. The aim of this study is to investigate the use of emoticons in Twitter by Italian users, and to verify, by relying on corpus data and on statistical methodologies, some of the prevailing opinions on the use of emoticons: that they are technically-driven resources, that they are mostly used by young people, and more often by females, and that they are superficial and easy ways of expressing emotions using images instead of words. A mixed-effects model analysis has shown that the use of emoticons on Twitter is affected by a complex interaction of cultural, technological, situational and sociolinguistic variables.