The definitions seem kind of arbitrary, online friend seems to mean either:
1. friend who you primarily communicate online
2. friend where initial contact was made online
Option 1 seems odd, especially for friends who have moved. Are they reclassified as "online friend"? Option 2 represents only a single moment in time and seems to have little bearing on everything past that initial contact.
Also some people seem to classify "real friend" as "friend that I physically see on a regular basis".
> Option 2 represents only a single moment in time and seems to have little bearing on everything past that initial contact.
It has bearing indefinitely because it means you likely need to travel in order to interact offline.
Friends who've moved might or might not eventually demote to "online friend" status, in a similar way to how they might or might not demote to "used to be friends" status, I suppose.