In free software, there is a fairly smooth continuum between purely internal discussions and public relations statements. This is partly because the target audience is always ill-defined: given that most or all posts are publicly accessible, the project doesn’t have full control over the impression the world gets. Someone—say, a slashdot.org editor—may draw millions of readers’ attention to a post that no one ever expected to be seen outside the project. This is a fact of life that all open source projects live with, but in practice, the risk is usually small. In general, the announcements that the project most wants publicized are the ones that will be most publicized, assuming you use the right mechanisms to indicate relative newsworthiness to the outside world.
— Karl Fogel, Producing Open Source Software
I personally think this viewpoint is somewhat optimistic…
I would guess that the size or popularity of a project skews this. When lots of people are reading your development lists and bugs, a lot of inconsequential things can get blown up.