How can a friend or client review and comment on a shared LrWeb collection without having to set up an Adobe account?
Lightroom Web is the browser-based part of Lightroom Mobile. When Lightroom uploads photos (smart previews) to Adobe’s servers for Mobile, they can also be made available to other clients such as a web browser, and that’s what’s being done at https://lightroom.adobe.com/ .
LR Web is designed with a Facebook-like mechanism for allowing friends/clients to mark pictures as “Favorites”, and you can use this feature to allow them to select images they might want. These choices appear automatically in LR, and you can add your own responses in LR.
One awkward detail is that the client needs an Adobe account. This feature is pretty new and has already changed quickly, so I wouldn’t be surprised if it changes to allow other ways of authenticating comments. But it’s easy to imagine people may be reluctant to sign up, even if the account is free.
For now, you can always set up a dummy account and tell people to log in using that user name and password.
If you need more than one person to view a set of images, just duplicate the collection and sync it too (this doesn’t mean extra uploading). So, for example, client John might log in using mydummyadobeID and has the URL from the Shoot-John collection, while client David would use exactly the same ID to view the Shoot-David collection.