Kelly and I went through the MovableType MySQL database and closed over 120 old blog entries with open Trackback pings. This involved the repetative task of going row by row and changing a 1 to a 0.
I also deleted the trackback spam entries from the database, most advertising on-line gambling.
Since we don’t really use trackbacks (we all seem to use comments instead), I recommend not leaving this option open when posting a new entry.
And for the moment, no one can leave a trackback because I changed the name of mt-tb.cgi until I can implement some kind of security to prevent trackback spam.