diff --git a/oyster/core.py b/oyster/core.py
index 86fcb55..f6441d1 100644
--- a/oyster/core.py
+++ b/oyster/core.py
@@ -91,24 +91,37 @@ class Kernel(object):
             any keyword args will be added to the document's metadata
         """
         if doc_class not in self.doc_classes:
-            raise ValueError('unregistered doc_class %s' % doc_class)
+            error = 'unregistered doc_class %s' % doc_class
+            self.log('track', url=url, error=error)
+            raise ValueError(error)
 
-        tracked = self.db.tracked.find_one({'url': url})
+        # try and find an existing version of this document
+        tracked = None
 
-        # if data is already tracked and this is just a duplicate call
-        # return the original object
+        if id:
+            tracked = self.db.tracked.find_one({'_id': id})
+
+        if not tracked:
+            tracked = self.db.tracked.find_one({'url': url})
+
+        # if id exists, ensure that URL and doc_class haven't changed
+        # then return existing data (possibly with refreshed metadata)
         if tracked:
-            # only check id if id was passed in
-            id_matches = (tracked['_id'] == id) if id else True
-            if (tracked['metadata'] == kwargs and
-                tracked['doc_class'] == doc_class and
-                id_matches):
+            if (tracked['url'] == url and
+                tracked['doc_class'] == doc_class):
+                if kwargs != tracked['metadata']:
+                    tracked['metadata'] = kwargs
+                    self.db.tracked.save(tracked, safe=True)
                 return tracked['_id']
             else:
-                self.log('track', url=url, error='tracking conflict')
-                raise ValueError('%s is already tracked with different '
-                                 'metadata: (tracked: %r) (new: %r)' %
-                                 (url, tracked['metadata'], kwargs))
+                # id existed but with different URL
+                error = ('%s already exists with different data (tracked: '
+                         '%s, %s) (new: %s, %s)' % (tracked['_id'],
+                                                    tracked['url'],
+                                                    tracked['doc_class'],
+                                                    url, doc_class))
+                self.log('track', url=url, error=error)
+                raise ValueError(error)
 
         self.log('track', url=url)
 
@@ -117,7 +130,7 @@ class Kernel(object):
                       versions=[], metadata=kwargs)
         if id:
             newdoc['_id'] = id
-        return self.db.tracked.insert(newdoc)
+        return self.db.tracked.insert(newdoc, safe=True)
 
     def md5_versioning(self, olddata, newdata):
         """ return True if md5 changed or if file is new """
diff --git a/oyster/storage/s3.py b/oyster/storage/s3.py
index f77e9a6..d47901a 100644
--- a/oyster/storage/s3.py
+++ b/oyster/storage/s3.py
@@ -8,7 +8,13 @@ class S3Storage(object):
 
     def __init__(self, kernel):
         self.s3conn = boto.connect_s3(settings.AWS_KEY, settings.AWS_SECRET)
-        self.bucket = self.s3conn.create_bucket(settings.AWS_BUCKET)
+        self._bucket = False
+
+    @property
+    def bucket(self):
+        if not self._bucket:
+            self._bucket = self.s3conn.create_bucket(settings.AWS_BUCKET)
+        return self._bucket
 
     def put(self, tracked_doc, data, content_type):
         """ upload the document to S3 """
diff --git a/oyster/tests/test_kernel.py b/oyster/tests/test_kernel.py
index 90a4719..9fa95a6 100644
--- a/oyster/tests/test_kernel.py
+++ b/oyster/tests/test_kernel.py
@@ -83,28 +83,27 @@ class KernelTests(TestCase):
         id2 = self.kernel.track_url('http://example.com', 'default', pi=3)
         assert id1 == id2
 
-        # test setting id
+        # test manually set id
         out = self.kernel.track_url('http://example.com/2', 'default',
                                     'fixed-id')
         assert out == 'fixed-id'
 
-        # can't track same URL twice with different id
-        assert_raises(ValueError, self.kernel.track_url, 'http://example.com',
-                      'default', 'hard-coded-id')
-        # logged error
-        assert self.kernel.db.logs.find_one({'error': 'tracking conflict'})
+        # can't pass track same id twice with different url
+        self.kernel.db.logs.drop()
+        assert_raises(ValueError, self.kernel.track_url,
+                      'http://example.com/3', 'default', 'fixed-id')
+        assert 'already exists' in self.kernel.db.logs.find_one()['error']
 
-        # ... with different metadata
-        assert_raises(ValueError, self.kernel.track_url, 'http://example.com',
-                      'default')
-        # logged error
-        assert self.kernel.db.logs.find_one({'error': 'tracking conflict'})
+        # ... or different doc class
+        self.kernel.db.logs.drop()
+        assert_raises(ValueError, self.kernel.track_url,
+                      'http://example.com/2', 'change-hook', 'fixed-id')
+        assert 'already exists' in self.kernel.db.logs.find_one()['error']
 
-        # ... different doc class
-        assert_raises(ValueError, self.kernel.track_url, 'http://example.com',
-                      'special-doc-class', pi=3)
-        # logged error
-        assert self.kernel.db.logs.find_one({'error': 'tracking conflict'})
+        # different metadata is ok, but it should be updated
+        self.kernel.track_url('http://example.com/2', 'default', 'fixed-id',
+                              pi=3)
+        self.kernel.db.tracked.find_one({'_id': 'fixed-id'})['metadata']['pi'] == 3
 
     def test_no_update(self):
         # update
diff --git a/oyster/tests/test_storage.py b/oyster/tests/test_storage.py
index 23c7d77..9e92540 100644
--- a/oyster/tests/test_storage.py
+++ b/oyster/tests/test_storage.py
@@ -1,3 +1,6 @@
+from nose.plugins.skip import SkipTest
+
+from oyster.conf import settings
 from oyster.core import Kernel
 from oyster.storage.s3 import S3Storage
 from oyster.storage.gridfs import GridFSStorage
@@ -21,6 +24,8 @@ def _simple_storage_test(StorageCls):
 
 
 def test_s3():
+    #if not hasattr(settings, 'AWS_BUCKET'):
+    #    raise SkipTest('S3 not configured')
     _simple_storage_test(S3Storage)