We are in the same situation, we are in the process of migrating to ByD and existing users of Google Apps for about 18 months. We'd like to see the same level of interoperability that ByD has with Outlook when using Gmail/Google Calendar etc. From the SAP help, it's this functionality: You can synchronize your contacts, e-mails, appointments, and tasks to and from Outlook; create service requests in the system from incoming e-mails; and associate e-mails, tasks and appointments with SAP Business ByDesign accounts, campaigns, opportunities, and leads.
There was lots of buzz about this mid 2012 with talk of it being realised in FP4.0, however the only integration I have seen is being able to select files from Google Drive when attaching to the ByD system.