Is this functionality provided by Dojo or Dijit? A Dojo extension?
Not that I know of, but this would be a useful feature (and something I need fairly soon anyway) so I created one.
I'll put it up on my github account at some point, but for now just find it at http://telliott.net/dojoExamples/timeago.zip.
I've not tested in IE, just Chrome and FF at the moment. LMK if you have any problems.
Tom