Index: wp-includes/plugin.php
===================================================================
--- wp-includes/plugin.php	(revision 25008)
+++ wp-includes/plugin.php	(working copy)
@@ -22,26 +22,31 @@
 /**
  * Hooks a function or method to a specific filter action.
  *
- * Filters are the hooks that WordPress launches to modify text of various types
- * before adding it to the database or sending it to the browser screen. Plugins
- * can specify that one or more of its PHP functions is executed to
- * modify specific types of text at these times, using the Filter API.
+ * WordPress uses filter hooks to make it possible to modify data of various types
+ * before it is added to the database and/or sent to the browser screen.
  *
- * To use the API, the following code should be used to bind a callback to the
- * filter.
+ * Using the Plugin API, a plugin can modify data via these filter hooks by assigning
+ * one or more of its PHP functions to be used as a "callback". When a filter hook
+ * is later evaluated, each callback function is run against that value in order of
+ * priority until all callback functions have run their course.
  *
+ * The following example shows how a callback function is bound to a filter hook.
+ * Note that $example is passed to the callback, (maybe) modified, then returned:
+ *
  * <code>
- * function example_hook($example) { echo $example; }
- * add_filter('example_filter', 'example_hook');
+ * function example_callback( $example ) {
+ * 	// Maybe modify $example in some way
+ * 	return $example
+ * }
+ * add_filter( 'example_filter', 'example_callback' );
  * </code>
  *
  * In WordPress 1.5.1+, hooked functions can take extra arguments that are set
  * when the matching do_action() or apply_filters() call is run. The
- * $accepted_args allow for calling functions only when the number of args
+ * $accepted_args parameter allows for calling functions only when the number of args
  * match. Hooked functions can take extra arguments that are set when the
- * matching do_action() or apply_filters() call is run. For example, the action
- * comment_id_not_found will pass any functions that hook onto it the ID of the
- * requested comment.
+ * matching do_action() or apply_filters() call is run. For example, the comment_id_not_found
+ * action will pass any functions that hook onto it the ID of the requested comment.
  *
  * <strong>Note:</strong> the function will return true no matter if the
  * function was hooked fails or not. There are no checks for whether the
@@ -114,12 +119,19 @@
  *
  * The function allows for additional arguments to be added and passed to hooks.
  * <code>
- * function example_hook($string, $arg1, $arg2)
- * {
- *		//Do stuff
- *		return $string;
+ * // Our filter callback function
+ * function example_callback( $string, $arg1, $arg2 ) {
+ *	// Maybe modify $string
+ *	return $string;
  * }
- * $value = apply_filters('example_filter', 'filter me', 'arg1', 'arg2');
+ * add_filter( 'example_filter', 'example_callback', 10, 3 );
+ *
+ * // Apply the filters by calling the 'example_callback' function we
+ * // "hooked" to 'example_filter' using the add_filter() function above.
+ * // - 'example_filter' is the filter hook $tag
+ * // - 'filter me' is the value being filtered
+ * // - $arg1 and $arg2 are the additional arguments passed to the callback.
+ * $value = apply_filters( 'example_filter', 'filter me', $arg1, $arg2 );
  * </code>
  *
  * @package WordPress
@@ -708,7 +720,6 @@
  * @uses $wp_filter Used to process all of the functions in the 'all' hook
  *
  * @param array $args The collected parameters from the hook that was called.
- * @param string $hook Optional. The hook name that was used to call the 'all' hook.
  */
 function _wp_call_all_hook($args) {
 	global $wp_filter;