I signed up with my work address, created a new Workspace and tried to invite some of my colleagues to share it. All seemed to proceed fine... but they didn't get the invitation e-mail, and I didn't get the copy I had requested.

To test it out, I tried 'Share with More' and invited a personal e-mail address of mine... I now see where the problem is!

The Sender of the invitation is my own e-mail address; rather than being sent from a generic Microsoft e-mail address, it looks as though the e-mail has been sent from my own work address. I think this is spoofing, no?

The e-mail is clearly blocked by our corporate mail filters; we have a long standing rule that any incoming mail which appears to be sent from an address on our own domain will be blocked. This rule captures a large amount of spam so I have no interest in asking the mail admins to tinker with the rule. Is there any other way I can get invitations out, or any other way I can provide the Workspace URL to my colleagues? Am I right that every invitee will get a unique URL?

The reason we are using your email as opposed to a generic Office Live one is to avoid looking like spam. Despite the filtering problem, seeing an email coming from a friend rather than a service is much more inviting than an automated one.

 Nonetheless, we understand your problem and we are working to solve this. In the meantime, I can recommend a workaround:

1. Share the workspace like you would today by adding your friends' email address. The email will get blocked
2. Copy the URL from the browser address bar while you are navigating your workspace and paste it on an email that send to your friends using your favorite email client. Your friends will be able to click on the link and see the workspace. The only issues is that they need to be logged-in. Otherwise they will be presented with a strange "can't access' message

We actually set both a "From" header and a "Sender" header on the sharing e-mails that we send.  The "From" header will be your address and the "Sender" header is a Microsoft address.  Different mail clients and servers may treat this in different ways; for example, Outlook will show the message as coming from "Microsoft Office Live Workspace [welcome@officeliveemail.com] on behalf of your@address".

There are actually checks that receiving mail servers can do to validate the legitimacy of our "Sender" header (SPF).  There may be some tweaking that can be done to your mail filters here.  However, in the meantime the workaround already suggested will work fine.

-- David.