Simple CMS For Mixed Mac/Windows Team?

Quasar Sera writes "I am looking for a content and/or project management solution for a marketing research team using both Macs and PCs. Ideally it would support document sharing, metadata/tags, search capabilities, revision control, and the ability to share documents easily with people from outside the team without any software installation or login required. It may be tricky to configure (since I will be doing that) but must be dead simple to use for the rest of the team. We rely mostly on Word, Powerpoint, and Excel (all in their native file formats) for our work, so it would be a large number of fairly small files. Any and all advice would be appreciated."