Depende de la población a la que vas a investigar. Primero debes establecerla para seguir un proceso muestral o tener bien claras las características de a quien buscas.
What is exactly your criteria to measure social media Or Facebook Does it related to Measure brand awareness / brand / brand loyalty / brand value etc.
Then easily you can do your research .. Many Thanks
The ideal strategy is to distribute the questionnaire by using the Facebook advertising platform where simply you can reach your target audience to a greater extent.