diff --git a/app/helpers/boxes_helper.rb b/app/helpers/boxes_helper.rb
index 4f72a9a..dce741a 100644
--- a/app/helpers/boxes_helper.rb
+++ b/app/helpers/boxes_helper.rb
@@ -41,27 +41,30 @@ module BoxesHelper
 
   def display_block(block, main_content = nil)
     content = block.main? ? main_content : block.content
-    result = 
-      case content
-      when Hash
-        content_tag('iframe', '', :src => url_for(content))
-      when String
-        if content =~ /^https?:\/\//
-          content_tag('iframe', '', :src => content)
-        else
-          content
-        end
-      when Proc
-        self.instance_eval(&content)
-      else
-        raise "Unsupported content for block (#{content.class})"
-      end
+    result = extract_block_content(content)
 
     classes = ['block', block.css_class_name ].uniq.join(' ')
 
     box_decorator.block_target(block.box, block) + content_tag('div', result + box_decorator.block_edit_buttons(block), :class => classes, :id => "block-#{block.id}") + box_decorator.block_handle(block)
   end
 
+  def extract_block_content(content)
+    case content
+    when Hash
+      content_tag('iframe', '', :src => url_for(content))
+    when String
+      if content =~ /^https?:\/\//
+        content_tag('iframe', '', :src => content)
+      else
+        content
+      end
+    when Proc
+      self.instance_eval(&content)
+    else
+      raise "Unsupported content for block (#{content.class})"
+    end
+  end
+
   module DontMoveBlocks
     # does nothing
     def self.block_target(box, block = nil)
diff --git a/app/models/block.rb b/app/models/block.rb
index 9273947..5f53a9d 100644
--- a/app/models/block.rb
+++ b/app/models/block.rb
@@ -16,8 +16,16 @@ class Block < ActiveRecord::Base
     _('A dummy block.')
   end
 
-  # TODO: must have some way to have access to request information (mainly the
-  # current user)
+  # Returns the content to be used for this block.
+  #
+  # This method can return several types of objects:
+  #
+  # * <tt>String</tt>: if the string starts with <tt>http://</tt> or <tt>https://</tt>, then it is assumed to be address of an IFRAME. Otherwise it's is used as regular HTML.
+  # * <tt>Hash</tt>: the hash is used to build an URL that is used as the address for a IFRAME. 
+  # * <tt>Proc</tt>: the Proc is evaluated in the scope of BoxesHelper. The
+  # block can then use <tt>render</tt>, <tt>link_to</tt>, etc.
+  #
+  # See BoxesHelper#extract_block_content for implementation details. 
   def content
     "This is block number %d" % self.id
   end
--
libgit2 0.21.2