When creating an account at Photoshop.com, you will be able to choose a personal URL for your gallery that you can share with others. Even with this, you can choose which of your photos you want to remain private or public so you have complete control over who can view your work.
Although the web site does allow you to perform several basic editing functions within the browser interface, these edits can take a while to process. I much prefer to do any editing on my own computer before uploading, but I can see where this functionality could be very handy if you needed to make a simple modification to a photo from a remote location.

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One feature that I really do love about Photoshop.com is the integration that is has with Photoshop Elements 7. In particular, you can define backup and synchronization preferences in PSE7, providing you with the option to automatically save your photos and any modifications to your online library. If you don’t want to use this feature for all of the photos in your collection, you can either turn it off completely or manually choose which photos to backup and synch.

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