People frequently ask about the etiquette of making minor edits to many old articles, say to retag them, or to correct typography or spelling. There seems to be consensus that this is bad manners, because it bumps the old post to the front page, thereby driving newer questions off the front page. But all other things being equal, we should prefer users to improve posts whenever possible, even when the posts are old: Part of the purpose of SE is to provide an archive of useful questions and answers.
The bumping behavior is important to prevent several abuses. For example, a user adding spam links to many old posts is very likely to be noticed because all the posts so edited would be bumped to the front page.
What if there was a “minor edit” checkbox on the edit form, available only to users with sufficiently high reputation, say in the 1000–3000 range, which would mark the edit as “minor” and prevent the edited post from being bumped to the front page? Established users would be able to clean up old articles without inappropriately forcing old posts to the front page. Abuse by established users can be handled by moderators.
Wikipedia has a somewhat similar “minor edit” box, available only to registered users, although the case is not exactly similar, because there is nothing analogous to bumping.