Need suggestions for long online reading experiences

Hi All,

My team is currently designing a report navigation structure that will
allow users to fluidly and meaningfully navigate through a long (think
60-100 pages) report.

Each report will have multiple sections and sub-sections. Each
sub-section will contain both text and information graphics.

We know from our research that some users will simply download the full
report as a PDF; however, a high number of users will need to easily
find, consume, re-use, and refer to only specific sections of the
report.

Hence the need to guide them to those sections in a quick, intuitive
way.

I am looking for good online experiences (or real-world analogues) that
help users move through long pieces of content.

Examples might include features such as:

* Persistent table of contents
* Quick access to an index
* Elegant search functionality
* Expandable / collapsible sub-sections

Thanks very much!

-adam