The problem is it's not subtle at all; there's a handful of those features that, when combined, end up being overbearing and noisy: "3 people looked at this listing within the past 3 days! 12 rooms left at this rate!" I don't care. I'm looking to book business or vacation travel. If a spot fills up I'll just go somewhere else. It'll be fine either way.
I don't use them anymore for that reason. Old soul (me) is old. (I'm probably in a minority, judging by their advertisement budget.)