As a related aside: Does anyone know why arXiv has no system of public comments or (even better) a public peer review system built in? Whenever this topic comes up at a (CS) conference, everyone is for that, and yet, arXiv is functionally the same for quite a few years now.
Imaging what you could do with a social-network like publication database (research-gate sort of is, but it doesn't think big enough and the UX is confusing, imho). Every publication became a "post" so to speak. You could easily include discussions (both on the paper, as well as general discussions), ratings, user curated lists (instead of expensive journals), host links to any relevant non-paper data. Funding could be provided by Universities, or by means of a registration fee, or simply with an ad supported model. Targeted ads will probably bring in a relatively high CPM due to the target audience.
Incidentally, while we're at it, we could also get rid of strict formatting guidelines and super-formal writing, some of the best papers I've read are informal. And it's a very modern thing to do anyway, old papers by Kelvin and the like read much better than what we have to write these days.