[jackewiehose]

> It seems like the colon is too ambiguous (is used as a protocol delimiter, delimiter for user/pass, delimiter for port).

and because that was still too boring they came up with ipv6

[mananaysiempre]

IIUC the IPv6 weirdness here is simply due to very unfortunate timing: IPv6 was being finalized at a time (first half of the 90s) when the Web (and with it URLs) was already nearly frozen but still not obviously important.

[chungy]

The colons also make IPv6 addresses unambiguous to IPv4 notation.