As I mentioned before, I've had well over 300 trackback/pingback spam notifications from dasBlog. Since this was well beyond what I was willing to mess with by hand, I whipped up a quick Outlook macro to do the work for me:

Sub DeleteTrackback()
    Dim oSel As Outlook.Selection
    Dim oItem As Outlook.MailItem
    
    Dim oShell
    Set oShell = CreateObject("Shell.Application")

    Set oSel = Application.ActiveExplorer.Selection
    For x = 1 To oSel.Count
        Set oItem = oSel.Item(x)
        
        If (Left(oItem.Subject, 19) = "Weblog trackback by") Or _
           (Left(oItem.Subject, 18) = "Weblog pingback by") Then
            Index = InStr(1, oItem.Body, "Delete Trackback:")
            If (Index <> 0) Then
                URL = Mid(oItem.Body, Index + 18)
                URL = Left(URL, Len(URL) - 1)
                
                oShell.ShellExecute URL, "", "", "open", 1
            End If
        End If
        
    Next
End Sub

To use this macro, create a new macro and paste the source code; then select all the "Trackback/Pingback" notifications messages and run the macro. It could obviously be customized to work on entire folders or whatever, but that I leave to you. One final suggestion: if you (like me) keep a 15-tab Firefox window open at all times, you may want to open a new window (not tab, window!) so that you can then close all the URLs at once.