[JoeMayoBot]

Part of the OAuth protocol requires a timestamp, which needs to be within the same 5 minutes of the Twitter server. If the timestamp is out of these bounds, Twitter returns HTTP 401 Unauthorized responses and nothing works.

[karmakaze]

I don't recall exactly when, but I do recall writing into some client program a server time request with local time taken when sending the request and having received the response. The delta to the midpoint time was used as an offset for further communication. There were many users with PCs that didn't have their time correctly set and it was an easier solution.