While this isn't strictly related to the development of boost, I believe it may be interesting to developers of boost, and I would also be very interested in hearing any opinions (good and bad) from users and developers of boost. I am currently in the process of implementing all applicable (sort, rotate, partition, etc..) functions in the C++ standard library using only calls to iter_swap. Obviously for those classes with expensive copies and cheap swaps (list, vector, map, set, etc) this is a big win, however it unfortunatly can be slightly slower for classes and types which fall on the basic definition of swap. Therefore there will be an implementation-specific type trait defined (name to be decided) which can be defined to enable the swapping versions of functions. I'm implementing much of this for my own personal usage, but I hope to submit the code to libstdc++-v3 (g++'s implementation of the c++ standard library). While this may not be quite as general as the ideas of "move symantics", it has the advantage of being implementable now, and providing some significant improvements. I would be interested in knowing if anyone has any comments, and also should such code be implemented in g++ if boost would be willing to add the compiler-specific extra information to mark any classes with efficent swap as such. Note: I am aware there are various ways of trying to approximate if someone has specialised swap, such as checking for a swap member function. However at least at first, it is my belief such a library should probably be strictly op-in. Thank you, Chris