On the plus side...
I'm writing for the Web! What is the correct description of this task?
Web writer? Content editor?

I'm working with subject matter experts.
They have enlisted my consultant services to edit and format web content.
I am the process expert.

Articles with practical advice http://www.webpagecontent.com/

What I've learned:

Tips for writing on the Web
Use frequent, bold headers. Two headers should be visible on each Web page.
Don't skip a space under the header in order to preserve relevant effect.
Use short sentences and few words.

Make each header and each link descriptive.
Never use italics or include the word introduction.