If the link is helpful or on point, why would that be a problem? The implied answer to the question is "I found your solution here." Why waste time and risk the ethical violation involved in copying over anything other than a short blurb? I think the link is fair to the content creator since he or she gets blog hits (or whatever) and good for the question asker if the link answers the question. It's not great for SO because the content is elsewhere and subject to change, but that's a issue any content aggregator has to deal with.