A valid point. I've been using Workflowy for a few months (I'm a long-time "outliner aficionado" who has happily jumped into using this tool with both feet due to some HN postings), and when it comes to entering work/professional data, I make small efforts to obfuscate key items. But some cannot be obfuscated w/o invalidating the content itself...

I haven't been sufficiently concerned/motivated to investigate their privacy policy further.

[edit:] https://workflowy.com/privacy/ may raise concerns; I need to review this policy later (and compare it to those of other free services such as Google which I also use).