I've been thinking about how much CRM functionality a small business actually needs.

For many freelancers, consultants and small teams, the main questions after sending an important email are pretty simple: Was it opened? When was it opened? And when should I follow up?

That's one of the reasons I built OpenDot, a lightweight Gmail extension focused on email open tracking and real-time notifications without requiring users to move their workflow into a full CRM.

I'm curious how people here see this: at what point does a business actually need a full CRM instead of a lightweight email tracking tool?