Whilst I can't compare fulcrum to confluence, I can compare Zim to confluence, and they are chalk-and-cheese. Zim was designed principally as hierarchical notes-on-steroids for personal use. There's no permissions beyond the file level. I have no love for confluence (or jira for that matter); we've used both and fight both. We now use xWiki across the org for shared knowledge -- it has good access controls -- displacing confluence. Data migration was easy. For local information management, we suggest people use the tool they are most comfortable with from {dropbox paper; evernote; zim; devon-think; apple-notes; xWiki}. (We are a Mac & Linux shop).