“…This review adopts the conceptual framework used by Lantz-Andersson et al (2018), with a distinction between formal and informal groups of teachers. Formal groups of teachers are those that have been organised from the 'top-down', by institutions such as universities, governments, companies or schools seeking to create an online community (e.g., Whitehouse, 2011;Vuorikari et al, 2015;Mercieca & Kelly, 2018); while the latter is organised from the 'bottom-up', typically created by individual teachers to meet an already existing need (Ranieri et al, 2012;Kabilan, 2016;Macià & García, 2016;Prestridge, 2017;Kelly et al, 2018;Tucker, 2019).…”