> Especially that this can be quite easily achieved with privacy lists I thought we did the contrary: introduce an invisibility extension because: a) Implementing this in a client using privacy lists is quite some work, is not atomic, has nasty corner cases that are hard to solve, and is even harder to implement if you take into account existing privacy lists, and b) Would avoid servers having to implement privacy lists (which is no longer in rfc3920) just to provide invisibility.
cheers, Remko
