What is this? Can I use it to control access to my objects for different user groups?

Wakewatcher,

This demo can explain this new feature of add access by email id:

http://www.bucketexplorer.com/documenta ... areABucket

This demo explains how to use this feature for collaboration. This is probably not what you are looking for. This feature can be compared to a shared document library of Sharepoint. Share by email id requires that the other user has a registered Amazon.com account, a developer account and S3 account on Amazon. If they use your bucket, you will be billed for all activity, but they still need a developer account.

I think your application is shared with "a lot" of clients on web. For that type of application, best way would be to host the dynamic content (scripts) on a hosted web server which allows some scripting language and host the static content on S3. This way, you can generate "signed URL" for each user session on the fly, which will expire after a few minutes.

There is a lot of community code available on Amazon's resource center for this. But if you are not comfirtable with scripting, we can probably help you out with that part and you can get good quality shared web hosting for under 10$ a month for this task (you don't need any database), just ftp & scripting support.

Saurabh