I've been an enthusiastic online traveler for about 15 years, maybe a little longer, and I've always wondered when the wonder of it would wear off. As long as I keep stumbling across things like this blog post about triangular letters used by Soviet soldiers to send news back home from the front in World War II I doubt it ever will. An excerpt:
Folding had one more advantage: that the content of the letter was easy to check. Therefore, it was forbidden to seal them in any way. The censors working at the front did not primarily search for letters reviling the system – according to the analysis of the surviving front letters, almost none of them includes any political reference or Stalin’s name –, but whether they include any indication from which military movements and plans could be deduced. These were erased with black ink, but the mail was still transmitted.