diff -urN saku-3.9.0/file/saku.ini saku-3.9.0-sage/file/saku.ini
--- saku-3.9.0/file/saku.ini	2011-01-03 20:30:33.000000000 +0900
+++ saku-3.9.0-sage/file/saku.ini	2011-01-22 20:34:09.000000000 +0900
@@ -10,3 +10,6 @@
 
 [Gateway]
 visitor: ^127
+
+[Application Thread]
+sage: yes
diff -urN saku-3.9.0/file/sample.ini saku-3.9.0-sage/file/sample.ini
--- saku-3.9.0/file/sample.ini	2010-11-20 12:04:18.000000000 +0900
+++ saku-3.9.0-sage/file/sample.ini	2011-01-22 20:09:57.000000000 +0900
@@ -129,3 +129,6 @@
 
 # Auto make thumbnail another size. (yes/no)
 force_thumbnail: no
+
+# sage. (yes/no)
+sage: yes
diff -urN saku-3.9.0/shingetsu/cache.py saku-3.9.0-sage/shingetsu/cache.py
--- saku-3.9.0/shingetsu/cache.py	2010-11-20 11:57:58.000000000 +0900
+++ saku-3.9.0-sage/shingetsu/cache.py	2011-01-22 20:18:23.000000000 +0900
@@ -672,11 +672,17 @@
         """Add new data cache."""
         self.standby_directories()
         rec.sync()
+        age = True
         if really:
             self[rec.idstr] = rec
             self.size += len(str(rec)) + 1
             self.count += 1
-            if self.valid_stamp < rec.stamp:
+        if self.valid_stamp < rec.stamp:
+            if config.sage:
+                if rec.get("mail", ""):
+                    if re.search("[Ss][Aa][Gg][Ee]", rec["mail"]):
+                        age = False
+            if age:
                 self.valid_stamp = rec.stamp
         if self.stamp < rec.stamp:
             self.stamp = rec.stamp
@@ -822,7 +828,13 @@
                         if cache.stamp < rec.stamp:
                             cache.stamp = rec.stamp
                         if cache.valid_stamp < rec.stamp:
-                            cache.valid_stamp = rec.stamp
+                            age = True
+                            if config.sage:
+                                if rec.get("mail", ""):
+                                    if re.search("[Ss][Aa][Gg][Ee]", rec["mail"]):
+                                        age = False
+                            if age:
+                                cache.valid_stamp = rec.stamp
                         cache.size += len(str(rec))
                         cache.count += 1
                         rec.sync()
diff -urN saku-3.9.0/shingetsu/config.py saku-3.9.0-sage/shingetsu/config.py
--- saku-3.9.0/shingetsu/config.py	2011-01-08 14:49:25.000000000 +0900
+++ saku-3.9.0-sage/shingetsu/config.py	2011-01-22 19:06:50.000000000 +0900
@@ -139,6 +139,8 @@
                              'Application Thread',
                              'force_thumbnail', False, 'boolen')
 
+sage = _get_value(_extconf, 'Application Thread', 'sage', False, 'boolen')
+
 client_cycle = 5*60         # Seconds; Access client.cgi
 ping_cycle = 5*60           # Seconds; Check nodes
 sync_cycle = 5*60*60        # Seconds; Check cache