Linking out can be good in many ways. 1. Google checks the relevance of the sites you are linking out to. [Only don't link out to unknown sites, because google also penalises you for linking out to suspicious sites.] And don't link out to the same site again and again, if it is not Wikipedia .I have seen people linking most terms to Wikipedia.. But don't link out to only Wikipedia either. Link out to other informative sites as well. 2. It sends out a trackback to the other site, and if it is a blog, and your content is intersting or better still..solicits a conversation, you might get a reciprocal, which is great for SEO. 3. Good outbound links makes for interesting reading, and learning. I have seen very wise use of excessive outbound links for each terms and phrases that are interesting..That gives instant reference..eg If I link out to a post by Matt Cutts that explains the relevance of Out bound links here in this thread, it would make very interesting reading. Also Prudent use of Links can be very informative. I learnt a lot from links.. I just love Links, both ways. Please add more reasons on why Outbound links can be good. You may also add any reason why it might be Bad.