Windows only: GO Contact Sync is a handy little synchroniser that keeps your Google (G) and Outlook (O) contacts in line. You run it once or schedule it, and customise how it handles your data.
iPhone only: A bad sync, or a few clumsy finger swipes, can leave you with missing, duplicate, or otherwise messed-up iPhone contacts. iDrive Lite is a free app that stores contacts in the cloud. It’s a simple app that exports your contacts to a space at the
Outlook add-on Xobni has integrated with professional social networking site LinkedIn to enhance your contact information with job and employer details when possible. Using Outlook but not Xobni?