MailNews:Minimizing Bandwidth Usage

Make Thunderbird more friendly for unreliable and low-bandwidth conditions.

Thunderbird currently has a number of features that could help in these conditions, such as 'offline folders', 'MIME parts on-demand' and caching. But these features do not always work well in both unreliable and low-bandwidth conditions or when combined together.

This wiki pulls together inter-related issues in one place for discussion and to propose a solution.