While working on the new Harvest Help Center, our team had a chance to look at some common web-app issues with fresh eyes. Asset upload is almost certainly a requirement of any modern document-based web site, usually for images or general downloadable assets. There are a few pre-built Rails plugins that address asset upload (most notably paperclip), but they require database tables and are often designed with server-side storage in mind. Having a robust server-side solution for assets provides many benefits, but we found they were unnecessary for the simple workflow we had in mind.
We worked at finding something simpler and came up smiling.