Private Sub Worksheet_SelectionChange _
  (ByVal Target As Range)
Dim selPF As PivotField
Dim strField As String
Dim strAdd As String
Dim myVal As String
strField = "Site"

On Error Resume Next
Set selPF = Target.PivotField
If Not selPF Is Nothing And _
    selPF.Name = strField Then
  myVal = Target.Value
  If InStr(1, myVal, "@") > 0 Then
    strAdd = "mailto:"
  End If
  ThisWorkbook.FollowHyperlink _
    Address:=strAdd & myVal, _
    NewWindow:=True
End If

End Sub