Silence is a multifunctional communicative feature with different sociopragmatic and pragmalinguistic functions. These factors have to be studied in context in order to explain in what situations silence occurs and how it is perceived and evaluated by speakers. To the date, there are no studies which deal with these linguistic and extralinguistic factors, nor with the pragmatic achievements or the social effects of silent acts within Spanish conversation. This paper will focus on explaining these issues and the existing links between them by testing social habits of 100 young informants and by analysing 662 silences in a corpus of colloquial conversations between 10 very close friends (15 hours total). The outcomes suggest that (1) there are several factors influencing the use and the evaluation of silence, such as context, communicative role (speaker/addressee), social relationship, gender and topic of conversation; (2) silence fulfils different discourse functions in everyday communication, such as structuring discourse and other epistemological, psychological and normative functions; and (3) the informants assign polite, impolite or anti-polite effects to silence depending on the communicative situation in which it occurs.