If you're like me you are a bit cynical regarding upgrades.
I need to see a feature that I need to really get jazzed by an upgrade.
In Context editing in Dreamweaver CS4 is that feature...but it's not for me.
I know Dreamweaver and have worked with it for years and use it to create, manage, edit and maintain web sites. I know HTML and CSS and how to ftp files to a server.
In Context editing is for my clients...who don't know Dreamweaver, don't know html, don't know how to edit a page in Dreamweaver and don't know, html, CSS or any other web technology.
What they need is a simple way to edit a web page on a regular basis without calling me to do it for them. What they need is InContext Editing which allows anyone to make simple edits to a web page in the browser.
For the time being I recommend you peruse this article for In Context editing on the Adobe Labs site InContext Editing on Adobe Labs
In a few weeks I'll report on my experience of implementing it on a site I'm working on.