Module development and code questions

Hi,

Anyone integrated gcards with drupal. Any gcards module avialable? gcards has many cool features.

gCards is a free PHP-based eCard system that is easy to setup and use.

http://www.gregphoto.net/gcards/index.php

Our association is working in a project to aggregate blog from local bloggers.
In order to generate tags automatically we look at www.tagcloud.com. Mmmh interesting they are using yahoo web service to get keywords. What about adding this feature to our site? In Drupal of course.

I have the following code:

Hi,

I'm a drupal Noob. I've been playing around with developing in Drupal for only about 2 days, and I've been busy digging through and learning the system. I'm building a new module: Associate. This is to handle displaying of specific information about a person. I don't want to create these as Drupal user accounts and use the profile module. :)

Should everything be a node in Drupal, or is it alright/wise to have data that are not nodes?
What are the benefits of making them nodes?

Please excuse the noobish question. For the most part I can infer the semantics of variable names which, when combined with a sufficient tenacity, helps me deconstruct the code I'm looking at. But I can't seem to figure out the significance of $op. Does this stand for something? (output is my current best guest, although I also considered ) Is it an arbitrary designation? Is it a universal convention in certain situations like $foo?. I've searched but the nature of $op makes it extremely frustrating

I am trying to create a module that implements a node that has a multi-stage submission process. The user fills out the node information like a regular node but upon submission they are passed to another form page which requests further information based upon the first form page they filled out.