Yes, I volunteer myself. I would need feedback on the best solution--as the one I previously outlined was just one way it could be done. Right now, below each post are the following options: Vote up, Vote down, Comments (#), Save, and Report. They could easily add "Mark a typo" or "Report a typo" that could pop out a new window in which you can alert the author of a typo that needs fixing.
In terms of effort vs. gain--you pose an interesting question. I would argue that it is worth the effort. This is a website about rational thought, so it seems fitting that it should have a smooth user interface that they're constantly trying to optimize. I also think any effort into finding a better way or creating a better system is always well spent because it creates an environment that nurtures innovative thinking and progress. So even though programming a new function would only have an incremental benefit to users, I think little things like this have a positive impact on the way people think. Web programming is such a flexible medium, allowing improvements like this--and just like people on this site put extra time and effort into the pursuit of truth and rationality, I think we should also put extra effort into optimizing our systems of interaction, making them as efficient as possible. Efficiency is the sister of rationality.
You should consider other solutions, since the first one you think of is unlikely to be the best/cheapest to implement. The "Edit" functionality already exists. Users above a certain karma level could be allowed to edit posts, as in the case of StackOverflow. The major cost is that there would need to be a way to revert changes to prevent vandalism. Morendil pointed out that DM are a bit harder to send than comments. If desired, that could be fixed cheaply. There are surely other solutions.
I don’t want to be too dogmatic about this claim, but Godzilla is unrealistic. I don’t want to be too non-dogmatic about this claim either. OK then, just how dogmatic should I be? I have all sorts of reasons for thinking that skyscraper sized lizards or dinosaurs don’t actually exist. Honestly, the most important of these is probably that none of the people who I imagine would know if they did exist seem to believe in them. I never hear any mention of them in the news, in history books, etc, and I don’t see their effects in the national death statistics. No industries seem to exist to deal with their rampages, and no oil or shipping companies lose stock value from lizard attacks. Casually, at least, Godzilla attacks don’t seem like the sort of basic fact about the world that people could just overlook. How confident should I be that Godzilla type creatures don't exist?
I can also fairly easily recognize good biological reasons not to expect there to be giant rampaging lizards. The square/cube law, in its many manifestations, is the most basic of these, but by itself is not completely decisive. I can imagine physical workarounds that would allow sequoia giganticus sized reptiles, but not without novel bio-machinery that would take a long time to evolve and would surely be found in many other organisms. I can even vaguely imagine ways in which biology might prove resistant to conventional military weaponry and ecological niches and lifestyles that might support both such biology and such size, though much of my knowledge of Earth’s ecosystems would have to be re-written. For all that, if I lived in a world where essentially all authorities did refer to the activities of godzilla giganticus I would probably accept that they were probably correct regarding its existence. What should a hypothetical person who lived in a world where the existence of Godzilla type creatures was common knowledge and was regarded as an ordinary non-numinous fact about the world believe?
Godzilla would be considerably more perplexing than thunderstones, and would have to be considerably better documented to be credible. Even with the strongest documentation I would have substantial unresolved questions, inferring that Godzilla’s native ecosystem must be quite different from any known (possibly inferring that the details are classified), and even wondering whether Godzilla was a biological creature at all as opposed to, for instance, a giant robot left behind by an advanced and forgotten civilization, a line of inquiry that would greatly increase my credence in secret history of all kinds. For the most part though, I would probably go about life as normal. Even Natural Selection, the most damaged part of my world-view, would endure as a great intellectual triumph explaining the origins of almost all of Earth’s life forms. Only peripheral facts, such as distant history and the nature of some exotic ecosystems would be deeply called into question, and such facts are not tightly integrated with the broader edifice of science. In a conversation with a hypothetical Michael Vassar who believed in Godzilla, the issue would typically not come up. Science in general would not be called into question in my mind, but should it be?