diff --git a/attract/shots/eve_hooks.py b/attract/shots/eve_hooks.py
index cd54f48..e9e4681 100644
--- a/attract/shots/eve_hooks.py
+++ b/attract/shots/eve_hooks.py
@@ -1,9 +1,12 @@
+import itertools
 import logging
 
 from attract.node_types.shot import node_type_shot
 from pillar.api.nodes import only_for_node_type_decorator
 import pillar.api.activities
 import pillar.api.utils.authentication
+import pillar.api.utils
+import pillar.web.jinja
 
 log = logging.getLogger(__name__)
 only_for_shot = only_for_node_type_decorator(node_type_shot['name'])
@@ -29,9 +32,24 @@ def activity_after_replacing_shot(shot, original):
     validation.
     """
 
-    # TODO: compare to original, and either mention the things that changed,
+    # Compare to original, and either mention the things that changed,
     # or (if they are equal) don't log an activity at all.
-    register_shot_activity(shot, 'edited shot "%s"' % shot['name'])
+    changes = list(itertools.islice(pillar.api.utils.doc_diff(shot, original), 2))
+    if not changes:
+        log.info('Not registering replacement of shot %s, as it is identical '
+                 'in non-private fields.', shot['_id'])
+        return
+
+    if len(changes) == 1:
+        (key, val_shot, _) = changes[0]
+        human_key = key.rsplit('.', 1)[-1]
+        if key == 'properties.status':
+            val_shot = pillar.web.jinja.format_undertitle(val_shot)
+        descr = 'changed %s to %s in shot "%s"' % (human_key, val_shot, shot['name'])
+    else:
+        descr = 'edited shot "%s"' % shot['name']
+
+    register_shot_activity(shot, descr)
 
 
 @only_for_shot
diff --git a/attract/tasks/eve_hooks.py b/attract/tasks/eve_hooks.py
index 5315674..94295ae 100644
--- a/attract/tasks/eve_hooks.py
+++ b/attract/tasks/eve_hooks.py
@@ -1,11 +1,13 @@
 import logging
 
+import itertools
 from flask import current_app
 
 from attract.node_types.task import node_type_task
 from pillar.api.nodes import only_for_node_type_decorator
 import pillar.api.activities
 import pillar.api.utils.authentication
+import pillar.web.jinja
 
 log = logging.getLogger(__name__)
 only_for_task = only_for_node_type_decorator(node_type_task['name'])
@@ -100,9 +102,24 @@ def register_task_activity(task, descr):
 
 @only_for_task
 def activity_after_replacing_task(task, original):
-    # TODO: compare to original, and either mention the things that changed,
+    # Compare to original, and either mention the things that changed,
     # or (if they are equal) don't log an activity at all.
-    register_task_activity(task, 'edited task "%s"' % task['name'])
+    changes = list(itertools.islice(pillar.api.utils.doc_diff(task, original), 2))
+    if not changes:
+        log.info('Not registering replacement of task %s, as it is identical '
+                 'in non-private fields.', task['_id'])
+        return
+
+    if len(changes) == 1:
+        (key, val_task, _) = changes[0]
+        human_key = key.rsplit('.', 1)[-1]
+        if key == 'properties.status':
+            val_task = pillar.web.jinja.format_undertitle(val_task)
+        descr = 'changed %s to %s in task "%s"' % (human_key, val_task, task['name'])
+    else:
+        descr = 'edited task "%s"' % task['name']
+
+    register_task_activity(task, descr)
 
 
 @only_for_task