One of the goals of foreign language (FL) education is to produce intercultural speakers. Telecollaboration can act as a catalyst for promoting language skills development, intercultural communicative competence (ICC), and multiple literacies. The significance of multimodal communicative competence (MCC) on the success or failure of a telecollaborative project and its interdependence with intercultural communicative competence (ICC) have already been established. The very few systematic reviews on ICC and second language (L2) or FL learning do not take into account the different modalities through which learners interact and co-construct meaning and intercultural competence. Drawing on ecological linguistics (EL) and semiotics, the present review contributes to the field of applied linguistics by reviewing online intercultural exchanges (OIEs) and ICC development in relation to the modality used for each exchange that is reviewed. Features of the context of each study that was conducted in either a K-12 or a university setting were coded according to a coding scheme and analysed quantitatively using descriptive statistics. The findings of studies conducted in university contexts, were reviewed in-depth inductively in relation to the impact of Web 2.0 tools -- and especially multimodality -- on learners' development of ICC. The exclusive focus on university contexts in the in-depth review stems from the frequency at which universities serve as contexts for OIEs, comprising in this case more than two-thirds of the reviewed studies. Analysis of the data suggests that multimodality in Web 2.0 tools and applications affects ICC development in multiple ways but more research on ICC and L2 and FL learners in multimodal environments needs to be conducted.