I've had the same frustration as the OP where the date wasn't included when I was looking for time-sensitive information.  It was a disservice to me-as-reader, and I ended up not reading the article and looking elsewhere, since I couldn't be sure of its timeliness.<p>If that article was timeless, it's because I hear about it again and again from other readers linking to it, not because there was no date on it.<p>Of course, I don't know what you write, nor have I seen the results of your a/b testing.  So shrug.