Relevant Outbound links to authority / quality websites on your blog / website can boost your organic rankings in Google and other search engines. Plus you are give a better experience to the visitor since he has more resource to follow after he’s done reading your article. Ted say:
1. Yes, outbound links can support or even improve good rankings.
2. People clicking on an outbound link and not returning did not find what they were looking for on your page anyway.
3. If rankings go up, then total traffic goes up. "Losing" a certain percentage of visitors to the outbound link is not really a problem because it’s a percentage of a higher number. So you still get higher sales.
4. Just because people click out doesn’t mean they don’t come back. Linking out to a valuable resource can be much appreciated by the end user.
Andy says – I am inclined to believe that outbound links to quality sites that match the theme of your site should be beneficial in the long run. If there are no outbound links, Googlebot has nowhere to go after it finishes your site.
HalfDec says – Outbound links will improve your ranking for the keywords in the anchor text in that link. For example, if I link to a site using the text "blue widget", that link makes both the target page AND my own page more relevant for the keyword in the anchor text. Outbound links also increase your visibility. It lets other websites know you exist.