We're building a website for a startup and we encourage using the "timeago" format for displaying dates (i.e. less than a minute ago, about 5 minutes ago, about a month ago, etc.) but the client argues that it's not used in the US, that people are just not used to it. I can make a list of hundreds of sites using it, but of course, I'm a geek. So in adition to the main question, what are the pros and cons of the "timeago" date format?