In response to 'Nor mine, now' which covers a lot of comments by other bloggers.
I completely agree with you, links are useful. Good authors know where to place good links.
I am in no way diminishing that value or importance of good authors adding valuable links.
What Hyperwords is about is not really about links though, but interactivity. There are implicit links to be sure, such as looking up a word's dictionary definition or its Wikipedia entries, much in the same way NLS did. But that is only one aspect of Hyperwords.
But there are also other commands, more tool like, such as 'print this (not the whole page), blog about this, tag this, email this and so on.
Others are designed to be just handy helpers, like the 'Go' commands, like 'go to URL' which just activates a URL which the author forgot to make live. Same for call using Skype and look up addresses on maps, nothing profound, it just helps sometimes.
But back to the issue of author defined links and letting people leave the page at will too easily (through Google search and news search and so on) - Hyperwords does not make any assumptions as to the quality of work it is being used on. A lot of work is poorly presented, but even if it is organized and well presented, why should the reader stop there?
When there is rhetoric, there is persuasion. Why should the reader trust all the assertions? If there is a name of a company, a politician, why not provide the means to check on company information and voting records?
The function of a knowledge worker is to generate new knowledge, to question statements and assumptions.
Hyperwords aim to help that. A little now, more in the future.