Recently active topics in PBwiki tagged with licensing

I recently started using PB Wiki. Currently it's for myself and I have plans to add 2 employees to it. My understanding is that does not constitute 'commercial use'. However, I keep getting nag screens and reminder lines about upgrading. The upgrades seem to indicate more than 3 users though. What's up with all the nag screens?

For licensing purposes, what's consitutes a "user"? We have 5-user license business license with a private wiki. We have 5 staff members who will have access of varying levels above "read". Will we need to upgrade our license to allow anyone else "read" access? Would the same be true for a public wiki? Would the same be true for a mostly-private pbwiki 2.0 with at least one "public" folder?

Thanks!