contextia has a useful article about writing good intranet content. Although it is aimed at intranets, many of the points outlined can be applied to web content in general.
The article breaks good content down according to the following principles – accessible, usable, useful – and provides a number of points for each.
As the manager of a corporate intranet I can certainly relate to the relevance much of what the article says, especially the last point (not only because it contains an English reference):
Get rid of old crappy content. Get the cricket bat out swinging for the ‘some may want to use it in the future so let’s just stick it up somewhere’ position.
This is something I see a lot whereby the intranet is seen as an archive for information rather than a repository for information that people need to do their jobs now.
I try to counter this by reminding content providers that the more information they add, the harder each piece will be to find.
However, you still get the person who wants to keep an archive of their department newsletters dating back over the past few years. You know, just in case someone will want to go back to an old one.