Honest question: why don't researchers normally do this? Those in the software development do this all the time: set up a tumblr/Wordpress/whatever blog and publish our findings. If I had a dime for every time I saw an article about some benchmark of tech X vs Y... If every research lab ran a blog-type setup where they published their findings (along with any other updates), the whole field could be revolutionized. T…
The short story is that scientist need "credit", as there are much more people that positions (not even to get a good position, just to get any). But the credit is given only for two things: publishing in already well-respected journals and getting citations.
In principle there is not problem with establishing an truly open journal. In practice - almost no one does (because doing anything but writing papers will very likely result in loosing academic job - as there is no credit for that, regardless how important).
However, there are people trying change the system; I wrote about it here: http://offtopicarium.wikidot.com/v1:open-science-2-0