However, if you utilize other Office 365 services than Exchange Online, you should be aware of the following important detail:
“All client access policy scenarios have the effect of blocking external access to Microsoft Lync Online and Office Subscription Services.”
Yes in effect that means that you will also block access to Lync Online and the the Office 2013 Click to run subscription service.
This information has also been added to the relevant TechNet documentation: http://technet.microsoft.com/en-us/library/hh526961(v=ws.10).aspx
Until later,
Henrik Walther