Can I give viewing permissions for Google Docs documents to users with no Google account (for example with a Yahoo account)?
Yes, but they will have to setup their Google docs account once they get the shared link.
If you share your document to their email address, wherever that is, they will get an email with a custom link.
That link will take them to a sign in page with the option to sign up. They can have a Google doc account with a yahoo email address or any address fro that matter, but they will have to have an account before it will give them access to modify the document.
Alternatively, you can make the document public, then they can access it without any credentials at all with just the shared link.
You just have to share your document with that email address.
The person with whom you have shared the doc will get a mail with a link to the documents and he'll be asked to sync all contacts with the Gmail id. That's it. The process is done. It actually gets bad while your sharing data which is constantly changing, that's where even your e-mail client like MS outlook also gives up.
I have a recruitment firm where in data keeps moving within the team and none of these tools help. I have been hoping for this new one called CollateBox for sharing spreadsheets with my team.