I personally feel that timestamp is the most important tag that any post or page or comment or product page or even a normal physical paper should have. Having a timestamp help assess users if the information is still relevant which I am not sure if the present day search engines would take care of. I came across one such site today which has no timestamp in the comments section which degrades the User Experience. I have found one of the few on the internet just today. As you are curious to know the site, it’s here – www.fluther.com .
The comments do not have a timestamp on them when a user commented. Atleast the timestamp on the post/question gives the user information that its more than 1 year old (relatively).
I was trying to find if textmate is worth it or not