Since they represent the cradle of social networks, the authors used the most recent research conducted mainly in the USA. The basic goals of this paper comprise: an overview of global trends relating to the media type-based advertising investments; listing the guidelines for developing a successful marketing campaign within the biggest social network - Facebook; considering the characteristics of Facebook advertising; underlining the importance of selecting the right social network when planning marketing campaigns and advertising, bearing in mind their specific traits (Instagram, Snapchat, Pinterest, YouTube), but also the preferences of different generations, and always starting from the very organization's goals. The forecasts relating to the advertising investment trends in the next three years, indicate that mobile internet advertising will be in the lead. Considering that social networks, Facebook in particular, rely on a vast number of users who mostly access them via mobile apps, their business development and marketing campaign potential is clear; thus, planning and implementing an organisation's presence and advertising strategy on social networks requires a lot of attention. Even though Facebook is still the most popular social network worldwide, Instagram has overtaken the throne among younger generations, and organisations increasingly use it to present their brands to the younger audience.