What are some defunct protocols or systems (X.400, UUCP, Lotus Notes)?

Early systems such as X.400, UUCP, and Lotus Notes once competed with internet email. UUCP in particular used what was called a bang path. An address could look like this

host1\!host2\!host3\!user

The sender had to know the exact path the message had to take across machines. It worked but it did not scale which is why SMTP and internet style addressing replaced it.

It was like having to plot every single island stop by hand instead of using a shared nautical chart.