Meta-design theory emphasizes that future use can never be entirely anticipated at design time, as users shape their environments in response to emerging needs; systems should therefore be designed to adapt to future conditions in the hands of end users. For most of human history, all design was meta-design; designers were also users, and the environments of design and use were one and the same. Technology introduced a divide between the skilled producers and unskilled consumers of technology, and between design time and use time. In our increasingly complex technological environments, tomorrow's meta-designers must be able to anticipate the environment in which the end users will work in order to provide the flexibility for users to craft their tools. By exploring and projecting forward current trends in technology use, we have identified key principles for meta-designers and suggest that using them as design heuristics will aid meta-designers in crafting systems for future end-users.