can you give an example of a good link that actually brings traffic?

[Jake]

Some established blogger will establish relationships with somewhat bigger bloggers, perhaps by first leaving insightful comments on their articles, later on they may offer to write a guest post for this more popular blog just to get an in body link back to his site. Some links are 1000x more powerful than others.

Aside from the direct traffic a link may being in, they also have the indirect benefit of increasing your site's search ranking by a miniscule amount, although more search ranking factors are coming into play, the perceived popularity of a site based on the number of others linking to it is still an important ranking factor. Just beware only visitors are supposed to be making links to your site, if the detect strange patterns the links can be ignored or cause your site to be penalized.