[Alan @ CIT]

Think if objects as "containers" for functions and variables The structure for the object is defined in a class. Take a look at includes/class_dm_threadpost.php.

You'll see that each class has various functions and varables defined within it. When vBulletin creates a new obkect, it uses something like:

$myObject = new vB_DataManager_Post();

Then, to access the variables and functions within the object in your code, you would use something like:

// Call a function
$myObject->verify_title("my post title here");
 
// Use a variable - prints the $post var (an array)
print_r($myObject->post);

Although OOP looks complicated when you don't know it, once you start learning it you'll relize all of the benifits it brings to a large project such as this. It seperates code in to functional, self-contained blocks (classes).

Take a look at http://www.phpfreaks.com/tutorials/48/0.php for an intro to OOP