I would argue we are already in a post-humanist world, and have been for some time, with the evolution of media, pointedly the internet, on group mentality, opinion and aligning of thought. All through intense, persistent and unrelenting social pressure, various political propagandas and essentially, marketing.
The coagulation of collective conscious intentions via the internet, dispersing opinion, values and philosophies, dispenses of the opinion forming skills of those exposed to it more and more as generations turn over. This has happened in stages since the introduction of the web and I believe can be prevalently seen in the west. In particular, in political states which lean more towards capitalism, as this effectively 'supercharges' the evolution of these mass influences.
We as humans are physically not really evolving any more, Darwinism isn't exactly hitting the spot for us, take a walk through any small town centre and I'm sure you'll find it hard to disagree (We do still hold the record as the best long distance land animal though if I'm not mistaken). We do however evolve behaviourally at an astronomical scale when compared to other species.
Whether the invocation of an effective 'hive mind' on our selves causes us to enter a state of 'post' humanism is open to debate of course, but i think on the Richter scale of change it scores rather high.
Much like me, I am also very high.