There are some questions and answers that need updating. For example, We need TeX markup ... has a link to Google Charts which leads to an Error 404 page. Would an add comment automatically inform the author of the question? What if the author is no longer a regular visitor? Is there another method of updating? Finally, this may not be the only question that needs updating. I will ask the question, however, I do not see an answer other than everyone being vigilant about it. How would you update ALL questions that need updating?
Community editing is part of the way the StackExchange network. Lower reputation users can suggest edits, while people with lots of reputation (over 3k I think) can simply edit directly. So you should feel free to suggest improvements.
The only thing I would ask is that no one overdoes it. Ideally, the front page is mainly made up of new questions. So editing half a dozen old questions a day is probably okay, but doing thirty is not!