Communication is imperative to the success of any project, especially with larger companies. One thing I think is important is for the project manager to have a proper communication stream with upper management and then that can be disbursed through the project team. One thing I have noted in industry is that have the R&D/quality folks that deal directly with the product should be aligned with the marketing/sales representatives. I have seem countless times that sales and marketing will present outdated information on back orders caused from quality or design related issues and that will cause information to be skewed to upper management. The heads of each department should due their due diligence and ensure that all other departments are in alignment. Emails are definitely a quick way to communicate and ensure there is traceability but having skype meetings has also proven beneficial in terms of communication. This way presentation or slides can be shared on a common screen and walked through together to ensure the entire message is being conveyed properly.