Module development and code questions

I have a small module that validates users creating new accounts using the 'validate' op in the _user hook. However this hook also gets invoked when they try to change any aspect of their profile.

How do I tell the difference between these two contexts?

The best stab I have is that $account['status'] is set to 1 when someone is trying to change their profile, but it isn't in either of the cases that a non-user is trying to create an account or an admin person is creating one for them.

But where is the documentation? Is this the right test or is there a better one?

The primary use of this would be either 1) online meetings or 2) meetings for folks in the local office. I know there are several existing modules for event notifications, but in place of getting notifications a day in advance, I want to figure out how to allow users to be notified in X minutes. It could just be a pulldown menu with times in 5 minute increments.

Is there any existing method for getting notifications in increments in minutes instead of days?

how can you change the preview button text? short of using the locale.module or image replacement, i can't figure it out, without hacking up node, since a button's text is controlled by its #value.

I am wanting to hide the normal create content menu item when a group is selected since we have separate create menu items for groups. I am wondering how and where I might be able to do this in the Drupal code. I am new to Drupal, so any help with this is greatly appreciated.

I am curious if it is possible to create a 'smart search' module, that module will not only index the whole published content and allow people to search it, but it will also learn how to rank the content on more criteria than available now.

currently i believe you can assign importance to keywords and other content but i think there should be more:

The module that I submitted to contrib on Friday afternoon still isn't visible via the project page at http://drupal.org/project/webfm. Have I made a hash of cvs? Is there a drupal cvs maintainer who could check this for me? It would be much appreciated.

-rob