I didn't post up my answer on the site because someone else had already covered it. In short, yes people still use them and given how easy they are to implement I see no reason not to put them onto your site.
Unless you use an ad service that doesn't support it I can't see a reason why you wouldn't implement (I can't speak for other languages but in ASP.NET MVC I could implement a feed in the time it took him to make that post)