It was nice because when you logged onto the forum and there was a new beer sent to you, you would get a "ding ding ding" sound and get all excited and see the pm and send a thank you to the person who sent it to you.
Of course bitcoin highly improves on this concept because paypal is not involved taking a cut and limiting the transaction size etc. Bitcoin is built for this kind of thing, why is this forum not taking advantage of it?? I did some reading and it looks like it's fairly simply to add as a feature using scripts. Here is a link to a discussion about that feature on that forum:
http://www.warriorforum.com/main-internet-marketing-discussion-forum/95343-anybody-else-miss-buy-me-beer-feature.html