Could insert automatically a link to the original wave, to keep a trace from it.
User could remove later if he don't want it.
This could be (partially) covered also by a bookmark or favorites tools center (like documents/wiki...) in user space...
Sometimes I find an interesting doc somewhere and I'd like to copy it to my personal space ("fork it"), and maybe make my own version of it.
Ideally, I should be able to do this with documents of groups that I am not member of.