Social media are already part of the communicative routines of most organizations, including communication agencies. Nevertheless, given their duty to serve other companies, these agencies should have an advanced understanding of these platforms, not only in their most profound sense but also in a time-advanced one. In other words, agencies should test emerging social media with the aim of knowing them in-depth and determining whether they serve their communicative purpose. It should be noticed that investment in digital advertising and actions with influencers are greater and greater. Besides, they are platforms that not necessarily remain unalterable, but some of them achieve their life cycle, even disappearing. On this matter, it is necessary to check if agencies really are working on the most recent social networks or only on those which are already consolidated. For such a research, the quantitative method, based on the content analysis, was adopted within a descriptive study. It was used on a sample of the ten communication agencies with the highest billing which operate in Spain. As secondary research objectives, it was considered to analyze the use that agencies do of social media which they are present in, to determine the existence of online content strategies, as well as to value the interaction level of these companies on online channels. The results show that most of analyzed agencies offer web 2.0-related services, such as digital strategy, online content management, monitoring and influencers relations. Social media talking, except for a few cases, communication agencies prefer to maintain a presence on the most consolidated social networks (Twitter, Facebook, Instagram, LinkedIn and YouTube). Furthermore, those are the ones that usually have links on their websites. This does not mean that agencies do not use the more recent applications, but that, mostly, they do not do this for their benefit as a brand. Otherwise they keep them in the background. In fact, some agencies use current platforms, such as Twitch or TikTok, publishing suitable content to their characteristics, which means that agencies know their possibilities, although their use is not still usual among them. Among the commonly used social networks, the activity of these agencies remains along the lines of what has already been concluded in previous academic papers: the purpose of information dissemination prevails with a self-promoting role. Communication agencies keep their social profiles updated and, during the month of research, they constantly published content, especially, information about themselves or about the communication sector, followed by news of common interest, clients news and projects carried out. Finally, although they published content frequently, the interaction with other users is low and, when it happens, it usually has, as mentioned, a self-promoting intention. In conclusion, communication agencies, as other kinds of organizations, are used to introduce social media work in their routines. However, it cannot be said that they are early adopters, at least to self-use. Probably, public relations professionals are researching and going deep in these new platforms, but in a private way, so agencies cannot, or prefer not to show their know-how by doing it. [ABSTRACT FROM AUTHOR]