The way I see it, it can't be an ethical site unless it's Free Software, not just open-source. Proprietary software is inherently unethical no matter what you're building.

Since you mention you are trying to build a team, and your focus is on ethics, I'd suggest making your company into a co-op. Each team member gets 1 share of the company on hire, they lose the share on quit/fire. Profits split evenly among all members. This is how all companies should be run. Capitalism is parasitic and unethical.