The main issue with file transfer is that it's a context where security and usability are nearly mutually exclusive features. To me we still have to address poi

The main issue with file transfer is that it's a context where security and usability are nearly mutually exclusive features. To me we still have to address point #1 which is how to get data in a transparent way from A to B (and C, D, etc.), whether none, one or more of them are on a PAN, LAN, WAN etc. Once the specifications are set, one can think of security and where to implement it in a way that doesn't affect usability. If I had to share a file on all my machines, I'd expect the software to let me drop/copy it into a directory knowing that anything put there will replicate on all my machines no matter where they are, that is, managing fixed/dynamic IPs, VPNs, machines momentarily off, etc. Same for less or more restricted transfers such ass for example passwords files or public documents. Everything should be transparent so that if I set up a similar system on granma PC I know that once she puts something into a public folder it's being shared with everyone (with her being warned about it beforehand) while a family only folder would have the content automatically shared (sent, replicated, backed up, etc) only to family members. To me it is very important that the software shows an abstraction of how would we operate in real life: public documents here and private others there, which would be very easy to understand: passwords, keys etc should be used only once to set up the system, unless they're revoked. But before all that, we must solve the #1 issue (see above). IPv6 should help to solve that, but it seems to me that implementing it as it should be would impact too many businesses currently profiting from simply being the cable that connects A, B, C, D etc.