When a user has been given access to show albums on other users' homepage, when sharing the album he can choose to show the album on the homepage that users see after logging in to FotoWeb.
If the FotoWeb site allows guest access, unathenticated users will have access to this in the same way as an authenticated user, and web search engines such as Google will be able to find and index the content.
You can set a release date and time and an expiry date at which the album will be removed from the homepage. If you also tick Allow downloads all users will be able to download assets from the album, including unauthenticated users.
The album owner can only grant download permissions if he has been given the right to allow downloads from albums through group rights, and if he has rights to download the original assets himself from the archives they originate in.