This paper results to be the first, though absolutely initial, overview of commenting platforms and other web 2.0 resources which were born for and within the astrophysical research community, from 2004 to 2016. Additional experiences, chiefly in the physics domain, were added for a total of twenty-one tools, inclusive of four items in the specific area of epijournals – plus four supplementary resources which have been simply mentioned or anyway much more synthetically described due to their specific features –, thus casting some light onto an unexpected richness and consonance of endeavours. These experiences rest on the contents of the pioneering database ArXiv, which adds to its universally recognized merits that of setting the grounds for web 2.0 resources, and research behaviours, to be put in place. These resources were surveyed substantially through the method of empirical evidence, partly routed by the web resources examined and by some of the literature, and are accounted for in a time sequence for their essential features. Most of the experiences retrieved are UK- and US-based, but other countries have been involved, such as Italy, the Netherlands and China. Final remarks are sketched. The results integrate the previous studies according to which the web 2.0 is presently of limited use for scholarly communication within the astrophysical community. Collaterally, some aspects of ArXiv's recent pathway towards partial inclusion of web 2.0 features are touched upon. The centrality of the scholarly literature for web 2.0 interactivity in astrophysics and – more presumably – in some other branches of the physics domain emerges as a plausible hypothesis and as a promising research suggestion. Further investigation is not only needed, but also absolutely hoped for.