Here’s the quick answer:
- Clear Formatting removes all “normal” styles – the things you find in the Format menu.
- Ignore Formatting places a magic style (pink) onto the text. This magic style causes the text to be exported as-is. This works great when you need to inject a tiny bit of HTML into the middle of some styled text and you don’t want to confuse the RapidWeaver rendering engine.
There is also one more that you didn’t mention too: Format > HTML > None – this will remove any of the special HTML styles (green) from the text.
The long answer I’ll paste into a separate post below…