The true value of undo lies not only in the ability to correct mistakes but also in encouraging exploration and learning which affects confidence in work. It is especially important that Web interfaces be forgiving and allow the users to get confidence since they mostly don’t have it.
Although this topic was discussed earlier, a recent debate with colleagues lead me to once again, briefly, point out the importance of undo feature. Back in 2007, A List Apart published Never Use a Warning When you Mean Undo, and we are still not there yet. It is a shame that in 2010 this feature is almost ignored on the Web. The problem is that designers overlook the possibility to undo things on Web. Except for a few examples, all you can have are confirmation dialogs. Forgiving, but not enough.
Users make easy decisions and perform fast actions when they know they are correctable. They are confident in using such systems. For instance, they easily add a product to shopping cart but they are not even closely confident when placing the order.
In his book The Laws of Simplicity, John Maeda writes about undoable purchases:
Knowing that a purchase is correctable later makes the shopping process simpler because you know that any decision made is not final. Indeed, today’s customers don’t expect to be held accountable for their purchase. Eager to build consumer trust in their brands, companies are willing to assume the extra risk inherent in a returnable purchase. The losses incurred by the cost of returned goods are outweighed by the gains in customer trust. That is the power of undo.
So let’s not forget that undo (and forgiveness in general) is much more than possibility to correct an error. It’s much more than Ctrl-Z.