This contribution will report on a study of the types of learning networks created in four online courses taught through the LMS Moodle, in a private institution of higher education in Portugal. The theoretical framework of the research was based on the works of Hrastinski (2008), Davies & Graff (2005) and, Vonderwell & Zachariah (2005) regarding online participation and the works of Arulchelvan (2011), Dawley (2007), Mazzolini & Maddison (2003), Nandi, Hamilton, & Harland (2012), Blignaut & Trollip (2003), Hew & Cheung (2008), Mazzolini & Maddison (2003) and, Anderson (2003) regarding the discussion forums. The SNA was based on the studies done by Marin & Wellman (2010), Wasserman & Faust (1994), Freeman (2004), Haythornthwaite & Laat (2010), Lemieux & Ouimet (2004), Bakharia, Heathcote, & Dawson (2009), Scott (2000), Hanneman & Riddle (2005), Müller-Prothmann (2007) and, Romero et. al. (2011). Data collection was carried out during the 1st and 2nd semesters of the academic year of 2010/2011. A mixed method case study research approach was used (both qualitative and quantitative techniques for collecting and processing data were used) as well as a qualitative structural analysis through a method of investigation called Social Network Analysis (SNA).