Basic SEO using drupal modules

People do say that 'search engines loves drupal' - but, is it true?
Its all a serious discussion going on the drupal forum board :

But, before entering there, let us look at few modules which makes our website more search engine friendly.

Most famous tricks are enable 'clean URLs', using pathauto module & use node words module.

clean URLs - where do i enable this?
go to Administer » Site configuration
Here you can find 'clean URLs' link - just click on it, then run the clean url test - if this succeeds your enable button becomes active, if it fails then follow this handbook page.

Know them in more detail in later postings!