If you had a chance to rebuild the internet, what would you change?
maw: 1) A better mail transfer protocol.  I don't view spam as inherently inevitable, but with SMTP it seems to be.2) Internationalization from the ground up.  Domain names are still effectively limited to 7 bit ASCII (even though "dots" are represented by '\0's in the DNS, which doesn't rule out UTF-8, in practice it doesn't work well).  I also still get mail I can't read, even when it's in a language I can, because of encoding issues (increasingly rare, but it still happens).