**2.1. Basic scientific context of altmetrics**

The introduction of alternative indicators for the quantification of scientific output and the associated resonance on the Internet can be traced back to a discussion by Priem et al. in 2010 [6]. They questioned whether focusing on the classical bibliometric indicators adequately reflects the scientific and social significance of research in the era of the Internet. During the course of this discussion, the expression "altmetrics" was coined as a collective term for alternative metrics, which include web-based information on scientific publications. Therefore, altmetrics can be regarded as a complement to classical bibliometric indicators providing new information that was previously unavailable, predominantly from the social media sector. This new information makes it possible to examine the reception of scientific publications, for example, on news sites, in science blogs, policy papers, and other web-based sources.

The altmetrics community can now look back on almost 7 years of research. On the one hand, the "visibility and presence of altmetrics are quite impressive" [8] because they are used as marketing tools by many scientific publishers, more than 300 publications on the subject have appeared, and there are even conferences dedicated solely to altmetrics. On the other hand, there is no uniform definition, and therefore no consensus on what exactly is measured by altmetrics and what conclusions can be drawn from the results [8–10]. The only consensus regarding the term definition is that the indicators discussed are intended to measure the attention paid to scientific output where bibliometrics reaches its limits—that is, on the Internet [6]. There is, however, a lack of any further and more detailed differentiation of such metrics.
