Web Development v/s Web Usability

I just read a book “Don’t Make Me Think” by Steve Krug. The tagline of the book is – A common sense approach to web usability.
The book is very interesting and the author has pointed out how web-designers/developers often overlook certain simple yet important web-usage patterns while designing a web page.
The author has discussed several usability traits that we need to keep in mind while designing web pages; like users mostly don’t read pages, they just scan/skim them.
Steve has also provided the Acid-test for good site design:
1) What site is this? [Site Id]
2) What page I am on? [Page name]
3) What are the major sections of this site? [Sections]
4) What are my options at this level? [Local navigation]
5) Where am I in the scheme of things? [‘You are here’ indicators]
6) How can I search?
If the page is well designed, you should be able to answer these questions without hesitation.
The book is merely a 3 hr read and you can just browse through it. Its full of illustrations and examples so it wont bore.