A requirement which comes up every so often is that external systems need to know about changes to content that lives in Sitecore. As with most technical problems, there are a variety of ways that you can solve a problem like this, and they all have different pros and cons. One of my colleagues has been working on a project like this recently, and the approach required there meant we bumped up against an interesting configuration challenge. If you're writing code that monitors content changes you might need to think about this:
In these days of standards compliance, most of the time you want the mark-up stored in your Rich Text fields to be well formed XHTML – which is exactly what the editor for these fields should give you. But what can you do if you come across a scenario where you don't want the mark-up to be changed by the editor for some reason?