account. Twitter’s interface, which in recent years has evolved to become somewhat similar to that of Facebook, presents a central chronological column, where the user posts his/her tweets, occasionally creating a “thread “which brings together sequentially various messages on a common theme, and where the user can read the tweets posted by those profiles which he/she chooses to follow. Moreover, thanks to several tags visible below each message, the user can “respond” to another tweet thereby opening an exchange with other users, share (retweet) other users’ messages with his/her own followers and indicate if he/she liked a message.

Finally, YouTube presents some unique characteristics, as it is a video sharing network accessible from any device without the need to follow certain profiles or to enter into contact with other users, in many cases, on request. Videos can be shared, valued positively or negatively by use of a thumb image which may be up or down, and commented on –after accessing a YouTube account– in a space where registered users’ messages may accumulate in just a few minutes. These comments, which the system normally orders chronologically, starting with the most recent, may receive responses, meaning this platform may also permit a sort of conversation. Such dynamics allow us to affirm that the networks are spaces where the expression of opinions, discussion and persuasion are predominant, and this explains the interest in extending analysis of discourse markers to diverse platforms, from a perspective which takes into account their use as a function of the degree of colloquiality or informality in the messages.

2.1. Markers and conceptional variation of written language and spoken language

The studies mentioned above were focused on the discursive and pragmatic functions of some markers in specific digital settings. However, this study is an attempt to offer a systematic study of the functions of those markers present in different social networks, bearing in mind the written/spoken conceptional variation of language. To this end, the standpoint of López Serena & Borreguero Zuloaga (2010) is taken into consideration, specifically on the use of markers in relation to written/spoken language variation. These authors observe the existence of a specialization among discourse markers regarding their appearance in oral or written discourse and point to the fact that numerous authors have taken up this idea (2010: 329). Having reviewed the studies of discourse markers in Spanish (Fuentes Rodríguez, 1987, 1993; Pons Bordería, 1998; Portolés Lázaro, 1998, 2010; Montolío Durán, 2001; Loureda Lamas & Acín Villa, 2010; Aschenberg & Loureda Lamas, 2011, among others), in which the relation between these particles and said variation is discussed, López Serena and Borreguero Zuloaga suggest that the analysis of their functions should consider written/spoken opposition as medial opposition –phonic as opposed to graphic execution– and as a gradual differentiation between the different ways in which discourse can be conceived and elaborated, that is, in relation to “the underlying conception of an enunciation and the mode of its verbalization” (López Serena y Borreguero Zuloaga, 2010: 338, authors’ italics). Thus, following Koch & Oesterreicher (1990 [2007]: 30), it is preferable to establish a differentiation not between written language and spoken language, but regarding communicative immediacy and distance.