I use Steam and I think the quirk they saw with pricing may in part be because their interface for Wish Listing and Price Watching is not... very intuitive. There IS a Wish List, but I used Steam for months before I figured out that it exists, and it doesn't send you notices when prices drop. This means that the only time you KNOW the price drops is when you search at the right time.
In contrast, when prices drop on Amazon, whether there's a "sale" or not, I know -- eReaderIQ sends me an email and I make the purchase then and there.
Tl;dr: Interesting article; Steam could be doing better as far as customer interfaces.