Windows Phone 8 allows users to back up their App List, Settings, Text Messages, Photos , and also their IE Favourites to SkyDrive.
Of these, only your photos are accessible from the web interface, but it seems, according to a recent leak released by LiveSide, that that is about to change , and users will have some level of access to their backed up device settings also.
LiveSide also expects a new Shared List Feature, where users can share a list of files in a bundle rather than just a folder, and this list would remain together on the receiving end. I can see this being useful for sharing collection of photos for example.
Users will also be able to mount shared folders locally on their PC, which should make collaboration with other users on projects much easier.
Read more detail at LiveSide.net here.