Greets people.

I'm trying to investigate how a search engine actually works. I need to know how:
  • It creates its database indexes for documents,
  • The concepts used to retrieve and rank documents
  • The techniques used to match documents with the queries

And if possible, the difficulties associated with searching the WWW

I'm googling for it now, but any help or direction from you guys will be a huge help.

Thanks, guys/gals.
Cheers