In Google Apps, what are “shared external contacts”?

Question

Looking at the features list for "Google Apps for Business", I see the following:

I am unable to find any information about this feature. What our small business needs is a way to share customer contacts across our Google Apps accounts. We would like contacts added by one employee to be available to everyone. I gather from similar, older questions that people are recommending third-party apps for this purpose. However, I'm curious to know whether this has finally been implemented by Google—without first having to upgrade our account.

Answer 1

No, it has not been implemented (that is, there's no GUI for it, but an API).

I believe the Shared external contacts feature was added to properly support syncing with Exchange servers, which have this feature. As such, you can only add shared contacts from your synced Exchange server, or, as you say, by using a third-party application that you can find in the Google Apps marketplace.