一直对 TrackBack 这个概念不是很理解。通过搜索引擎找了几篇文档，加上 Movable Type 自带的文档。读后概念清晰了一些。
什么是 TrackBack ?
TrackBack was designed to provide a method of notification between websites: it is a method of person A saying to person B, “This is something you may be interested in.” To do that, person A sends a TrackBack ping to person B.