Should I include the developers in these emails or not?
Increased direct communications, if done effectively, can improve the viability of a project. However, there are often pros and cons that must be considered. A lot depends on your project management framework, your project communications plan, and on the type of relationship you have with your client. In short, your mileage may vary.
Direct Contact with Agile Frameworks
The Agile Manifesto recommends direct interactions and customer collaboration whenever possible. This often stands in contrast to more traditional project management frameworks that value formal communications plans and carefully-managed client communications.
In the XP framework, direct contact between the development team and customers is both expected and required for success. Consider the following excerpt:
One of the few requirements of extreme programming (XP) is to have the customer available. Not only to help the development team, but to be a part of it as well. All phases of an XP project require communication with the customer, preferably face to face, on site.
In Scrum, sometimes the Product Owner proxies for the customer, while at other times the Product Owner facilitates appropriate interactions between the customer and the Development Team. Both proxy and direct communication methods have their pros and cons, and neither approach is actually mandated by the Scrum framework.
There Are Always Downsides
An unmediated interface between customers (or end users) and the Development Team is generally The Right Thing™ for mature agile teams, but there can certainly be counter-indications. For example:
- Teams or customers with low process maturity often need a mediator.
- Development teams with poor communications skills, or team members with significant personality deficits, should not be client-facing.
- Customers who are not on-board with a cooperative, negotiation-based, or back-and-forth approach to product delivery should be insulated from the Development Team.
- Projects based around "big up-front design" or that rely on detailed specification documents are often designed to minimize ongoing communications.
Whether or not the benefits of increased direct communications outweigh the potential social, political, or contractual consequences is something that each project must determine for itself. There simply is no universal answer to this complex consideration.