The social networks are offline. Universities are great at open collaboration, it's just not a kind of online collaboration where anybody can walk in and partak

The social networks are offline. Universities are great at open collaboration, it's just not a kind of online collaboration where anybody can walk in and partake. People spend a lot of time on a different type of communication: going to conferences, attending seminars, and meeting one-on-one. Why should it be online? Also keep in mind that a lot of mathematicians are also older, less tech-savvy. This might change in the next decade or two!