June 6th, 2007 | Published in Google Docs
When someone invites you to a view or edit a shared document or spreadsheet, you expect to be able to see it without having to jump over any walls (like a sign-in page or registration). We know this because you told us.
So now, if you invite someone who doesn't have a Google Account (or who does, but isn't logged in) to share a document or spreadsheet, he or she will be able to immediately view it. To edit, however, it's still necessary to first sign in or to create a Google account. Syd & Regina explained this in our Group.
To enable this feature, check the option on the "Share" tab called "Invitations may be used by anyone" - which will also allow people to forward your invitation email to others, so those people may gain access. You can always uncheck the box to limit access to those people you specifically invite. (They'll still need to be logged in to their Google account to create and edit documents and spreadsheets.)