This blog runs under Google's Blogger platform, which does not support TrackBacks or PingBacks. Instead, Blogger uses something called Backlinks. Backlinks information is obtained from Google's search results.
Newer links to posts show up as Backlinks. And rely on Google search to show those.
In the past, when this blog was hosted under other platforms -- TypePad and WordPress -- there was TrackBack support. We mentioned that a lot. However, under the current platform, support for TrackBacks and PingBacks no longer exists.