Writing for the web is to write in a very dynamic environment. When we write "rhetorically," we create text that does something with regard to the reader.
Readers come to the web to do things: learn something, purchase, find particular information.
Yesterday on the web I was after the following:
- Discover why slip-joint PVC fittings leak (sink repair)
- Learn about the features of my new "netvibes" aggregation page
- Find a phone number for S&T ceramic tile
- Check Tigers box score
In other words, in the web environments that we are talking about here, we don't assume that readers come to the our web pages merely to browse around. Most people come to our web pages for some specific reason.
Good web writing is rhetorical: it understands the dynamic, anticipates, and meets the reader's specific needs.