Google Apps – What Are Shared External Contacts

Shared contact in Google Apps will share only the contacts with emails from the same domain.

So the current implementation makes some sense only for big corporate implementations where it's hard to keep contact with people from inside the company.

From my knowledge, most of the Google Apps clients are small to medium, where you want to share external contact. Bad luck, you have to look for a third party service, like Is there a way to share/synchronize contacts between Google accounts? - free up to 3 accounts.

If you have doubts about it, then that's usually a pretty good "red flag" in my opinion.

The issue is that you are depending on a third party to store your security-related information. It just takes one bad employee (at your company as well as at a third-party company) to breach the trust and cause a lot of problems for you, and this is why encryption is so popular.

Although I have a great deal of confidence in Google's abilities to run their systems securely, and to select trustworthy employees, I still wouldn't store my passwords on their system unless I encrypted them on my own system before-hand (that way, they'd only get the encrypted version of the information).

Also consider the possibility of a third-party obtaining a court order for Google to provide full access to their customers' data. The nature of this court order could be that such access be kept secret from the customers as well. In this case I imagine that Google would have no choice but to comply with the law, and in the end you wouldn't really know who actually has access to your data.

My recommendation: Don't depend on third parties to store sensitive information if you don't have to (and if you have to, then only let them store encrypted versions of your data).