When I first lived in Hanoi I had a regular Xe ôm driver. His name was Dương. He drove me on his ancient Honda 50cc all over the city over a period of months. I'd visted his home, had tea with his mother, we ocassionally shared Bia hơi together, he recommended street stalls for me and, most importantly, he knew my routine. I didn't need to book him, he always arrived on time, waiting there on the pavement ready to take me to work.
Then one day, he didn't. The day after he didn't show up, I moved house, my worked changed, my routine likewise. I never saw Dương again. I've no idea what happened to him and there was no way I'd ever find his home again down that rabbit warren he took me along in a part of town alien to me.
This is before mobile phones were commonplace in Vietnam, pagers never really caught on as they did in South Korea and Japan. The Internet was for the very, very select few in the government. In fact, in 1997, you could only have an exceptionally basic, and expensive, dial up email service at home. Email was limited to small messages. Anthing over a certain number of kilobytes was simply too large for the network to handle and it was rejected. As far as I remember, Internet for home users didn't exist until at least 2000.
I doubt there's any way I would lose touch with a regular Xe ôm driver these days. Even if I wanted to.