http://www.mattcutts.com/blog/webmaster-communication/

This blog is by the chief Engineer for Google - He reveals information that you could not have gotten from the Google Guy Replies

Now, they will ban you for any little BullS***T - the site he is using as a example - just has two lines of Hidden text - but is a quality site - that is doing EVERYTHING else right

thanks very much for the very informative post and the link

Google sending "You are Banned" emails to Webmasters who violate Quality Standards

They should.

I think it's good that if you do something google doesn't like, they will tell you why.

But then I guess if you are making keyword stuffed text the same colour as the background, you already know why

ok so if i have hidden text i may get banned? but many sites hide text and use javascript to reveal it for things like content switchers... hmmm *shrug*

The text in question was the same colour as the background. This was a deliberate attempt to hide stuffed keywords to get higher rankings. Different to the javascript that you're proposing.