It's relatively common practice in academia to make announcements about results while they're still in pre-print form (particularly given how slow the peer review process is for some journals).
I've never announced my papers before they were accepted by a conference or journal (other than putting them on arXiv). I would certainly not let my university's press office mention my work if it was not fully peer reviewed. I've never seen this from my colleagues either.
It's common practice to "announce" in the sense that you email colleagues about it and give seminars. It's not common practice to do a press blitz, solely directed at an audience that will be unable to criticize it.
Well yeah, but a lot of the criticism is baseless. For example, you have people downthread saying things like "this can't be right because it's discrete", or, "it's inherently impossible for a theory of everything to make predictions", and so on. These aren't true at all.
Every physicist knows that if you want good criticism, you need to go to people with relevant expertise. That's what peer review is!
But they're doing that too. Given we live in the information age, why the hell not send it out in both a traditional research publication as well as a forum like this one? A lot of smart people out there in the world and if you can get 10,000 geniuses to look it over, who says it won't lead to either better criticisms or expansion of a potentially sound theory into other discoveries?
In a lot of physics areas, things move very fast, so generally people submit to a journal and arXiv simultaneously, in case someone else posts on arXiv first and goes down in history as first.
However, rarely are arxiv publications accompanied by such fan fare.
Why rely on narrow peer review when you can put the ideas out in public and receive much broader feedback. Most of that feedback will be noise, but the Wolfram crew are certainly able to find the signal in it and use that to improve or fix their ideas.
