Movable Type’s implementation of TrackBack has two closely associated objects or data types that bear the need for some explanation and clarification. Without going into too much technical details about the TrackBack protocol, let’s attempt to disambiguate between these two entities: TrackBacks and Pings.
A “TrackBack” is defined as a generic entity within a system that is eligible to receive pings, or has received pings in the past. A “Ping” then is the actual piece of data that correlates two otherwise unlinked entities together.
Why is this confusing? Well, colloquially bloggers and the industry at large has often used these terms interchangeably, and the manner in which these terms are used do not harmonize well with their technical implementation. This is a very difficult conflict to resolve, so it is important that you as the developer recognize that this consistency exists when dealing with the following callbacks.