I've now incorporated SlideShark into my daily workflow - using it for lots of presentations, large and small, internally and externally. One feature that would be great (in addition to the excellent suggestion about folders others have posted) is the ability to bulk-upload files. We get ppt's from our global offices and partners in batches - sometimes dozens at a time for products and services launches and customer support. Uploading them one-by-one can be a bit tedious! Another great feature would be some kind of synchonization ability with particular folders - kind of like a Dropbox feature for SlideShark.