diff --git a/modules/aggregator/aggregator.api.php b/modules/aggregator/aggregator.api.php
index f31413c..d605763 100644
--- a/modules/aggregator/aggregator.api.php
+++ b/modules/aggregator/aggregator.api.php
@@ -85,24 +85,24 @@ function hook_aggregator_fetch_info() {
  *   from $feed->source_string and expose it to other modules as an array of
  *   data items on $feed->items.
  *
- *   Feed format:
- *   - $feed->description (string) - description of the feed
- *   - $feed->image (string) - image for the feed
- *   - $feed->etag (string) - value of feed's entity tag header field
- *   - $feed->modified (UNIX timestamp) - value of feed's last modified header
- *     field
- *   - $feed->items (Array) - array of feed items.
- *
- *   By convention, the common format for a single feed item is:
- *   $item[key-name] = value;
- *
- *   Recognized keys:
- *   TITLE (string) - the title of a feed item
- *   DESCRIPTION (string) - the description (body text) of a feed item
- *   TIMESTAMP (UNIX timestamp) - the feed item's published time as UNIX timestamp
- *   AUTHOR (string) - the feed item's author
- *   GUID (string) - RSS/Atom global unique identifier
- *   LINK (string) - the feed item's URL
+ *   A stdClass object with the following properties:
+ *   - description: The human-readable description of the feed.
+ *   - image: HTML code that displays the image of the feed. It consists of an
+ *     image element and a link arount it.
+ *   - etag: The HTTP header response field ETag. You can copy from
+ *     $feed->http_headers['etag']. About its purpose, see
+ *     http://www.ietf.org/rfc/rfc2616.txt / 3.11 Entity Tags section.
+ *   - modified: The Unix timestamp when the feed was last modified.
+ *   - items: An array of feed items. The common format for a
+ *     single feed item is an associative array containing:
+ *     - title: The human-readable title of the feed item.
+ *     - description: The human-readable description of the feed item.
+ *     - timestamp: The Unix timestamp when the feed item was last published.
+ *     - author: The name of the author.
+ *     - guid: The RSS/Atom global unique identifier. This field is utilized to
+ *       be able to identify already aggregated items. Fallbacks to link when
+ *       guid is not available, so one of them is required to fill.
+ *     - link: The original URL of the feed item.
  *
  * @return
  *   TRUE if parsing was successful, FALSE otherwise.