diff --git a/pelican/generators.py b/pelican/generators.py
index 569d5f50..02131532 100755
--- a/pelican/generators.py
+++ b/pelican/generators.py
@@ -8,6 +8,8 @@ import os
 import math
 import random
 
+from blinker import signal
+
 from jinja2 import Environment, FileSystemLoader
 from jinja2.exceptions import TemplateNotFound
 
@@ -92,6 +94,7 @@ class ArticlesGenerator(Generator):
         self.dates = {}
         self.tags = defaultdict(list)
         self.categories = defaultdict(list)
+        self.signal = {'pelican_generate_context' : signal('pelican_generate_context')}
         super(ArticlesGenerator, self).__init__(*args, **kwargs)
 
     def generate_feeds(self, writer):
@@ -200,6 +203,8 @@ class ArticlesGenerator(Generator):
                 and self.settings['FALLBACK_ON_FS_DATE']:
                     metadatas['date'] = datetime.fromtimestamp(os.stat(f).st_ctime)
 
+            self.signal['pelican_generate_context'].send(self, metadatas=metadatas)
+
             article = Article(content, metadatas, settings=self.settings,
                               filename=f)
             if not is_valid_content(article, f):
diff --git a/plugins_samples/gravatar.py b/plugins_samples/gravatar.py
new file mode 100644
index 00000000..ca08984c
--- /dev/null
+++ b/plugins_samples/gravatar.py
@@ -0,0 +1,20 @@
+import hashlib
+
+from blinker import signal
+
+
+def add_gravatar(generator, metadatas):
+    
+    #first check email
+    if 'email' not in metadatas.keys()\
+        and 'AUTHOR_EMAIL' in generator.settings.keys():
+            metadatas['email'] = generator.settings['AUTHOR_EMAIL']
+            
+    #then add gravatar url
+    if 'email' in metadatas.keys():
+        gravatar_url = "http://www.gravatar.com/avatar/" + \
+                        hashlib.md5(metadatas['email'].lower()).hexdigest()
+        metadatas["author_gravatar"] = gravatar_url
+    
+    
+signal('pelican_generate_context').connect(add_gravatar)