The first email from space [video]
youtube.com
youtube.com
National Archives say that Bill Clinton had a public-facing email address in 1993 and that was probably around the time that (some) normal people were starting to get addresses and sending email.
In any case I'm not sure whatever photo-ops heads of state choose to do says a lot beyond something some advisor pitched to them.
IDK about the 76 email by the queen, but by the time the 90's rolled around I would have thought that electronic communications would have been pretty advantageous. Having everything printed out and hand delivered just seems like a waste of time. Particularly for something as large as the executive branch where there are so many secretaries that need to communicate.
Heck, DHS was primarily pitched and founded because of the 9/11 communication breakdown. I have to wonder how much of that was due to the fact that communications were papers flying around everywhere.
"The Final Days" White House Correspondents' Dinner Skit
While '98 feels a bit late Clinton was in office between '93-'00. This sounds like the timeframe e-mail became a critical part of daily life.
Edit: maybe they could use the laser links?