OpenID vs. OAuth

What is really the difference between OpenID and oAuth? They look just the same to me.

How Drupal works?

I have yet to see a comprehensive overview about how Drupal really works. Most of the tutorials are about lame things, like adding a module or configuring a site. Where is a flowchart about how the page gets generated? Most of the documentation is clumsy too. What's the best resource for learning how Drupal really works?

Can you Create your Own Hook in Drupal?

Is it possible to create your own hook in a Drupal module for other Drupal modules to consume? If not, is there a mechanism in Drupal for third party developers to provide hooks? If everything's been a no so far, where in the core are the list of hooks implemented.

Drupal 7 - custom View with custom table, no data showing up

I wrote a module to interface with Views 3 using Drupal 7, but when I create a view using my custom table as a data source, no data shows up. Here's my schema from MySQL:

Scaling Drupal

I am working on a Drupal based site and notice there are a lot of seperate CSS and js files. Wading though some of the code I can also see quite a few cases where many queries are used too.

How can i create a new tab in myaccount page using custom module in drupal

How can i create a new tab in myaccount page using custom module in drupal.Is there any hooks for that?

PHP is slower than it should be

Originally, I posted this on ServerFault ... but perhaps it is more of a PHP lingual question.