I found a nice seo snippet about the advantages of seo for targeted traffic, but also for our link building efforts. Webmasters are searching for link partners and they are searching on search engines (obviously).

From SEO Update:

“SEO also brings in targeted traffic because webmasters assume that when visitors arrive through search engines, they must have previously entered a search query.  SEO brings in “normal” traffic but also “webmaster” traffic.  What do you think that webmasters do when they want to exchange links?  They search for similar sites.  Again…. using search engines.  Putting emphasis on good SEO allows you to attract targeted visitors, to increase your site’s goodwill, and to build visibility with other webmasters as well.  It is almost a self-sustaining process.  If your site is well ranked in search engines, other webmasters will automatically approach you to suggest possible partnerships, which will reduce the amount spent doing “active” promotion.”