I was watching a lecture on keyword indexing that started off with a demonstration of an index to a book, which was being compared to indexing web pages. The statement was made that the keyword pointed the reader to a page where that keyword could be found, much like a search engine does for a web page.
Leaving aside the more complex roles that indexes for books play, such as giving alternative terms, classifying the nature of the occurrence of the term (definition, mentioned, footnote, etc.), cross-references, etc., I wondered if there is a difference between a page reference in a book index vs. a web page reference by a search engine?
In some 19th century indexes I have used, the page references are followed by a letter of the alphabet, to indicate that the page is divided into sections, sometimes as many as a – h or even higher. Mostly those are complex reference works, dictionaries, lexicons, works of that type, where the information is fairly dense. (Do you know of any modern examples of indexes where pages are divided? A note would be appreciated.)
I have the sense that an index of a book, without sub-dividing a page, is different from a index pointing to a web page. It may be a difference that has never been made explicit but I think it is important.
Some facts about word length on a “page:”
- The average number of words on a page in a book is about 400. (Word Count to Page)
- Google is said to recommend 250 – 300 words per page. (Word Count Per Page: Making It Just Right!).
- UIE reports that users don’t mind scrolling. (Long Pages Rule! and As the Page Scrolls)
With a short amount of content, average book page length, the user has little difficulty finding an index term on a page. But the longer the web page, the less useful our instinctive (trained?) scan of the page becomes.
In part because part of the page scrolls out of view. As you may know, that doesn’t happen with a print book.
Scanning of a print book is different from scanning of a webpage. How to account for that difference I don’t know.
Before you suggest Ctrl-F, see Do You Ctrl-F?. What was it you were saying about Ctrl-F?
Web pages (or other electronic media) that don’t replicate the fixed display of book pages result in a different indexing experience for the reader.
If a search engine index could point into a page, it would still be different from a traditional index but would come closer to a traditional index.
(The W3C has steadfastly resisted any effective subpage pointing. See the sad history of XLink/XPointer. You will probably have to ask insiders but it is a well known story.)
BTW, in case you are interested in blog length, see: Bloggers: This Is How Long Your Posts Should Be. Informative and amusing.