diamondhead, while I disagree with your tone I do agree with your premise. That is, with social bookmarking you create an army of curators and this data can certainly rival search engines (for any topic that has achieved critical mass).

One feature I would love to see with pinboard (or delicious) is recommended 'bookmark buddies'. That is, someone whose bookmark tastes overlap with mine (weighted by how rare the bookmark is) [1]. Recommending specific web articles is hard, but I find that following the full bookmark feed of 2 or 3 carefully selected individuals can often be more relevant than generic recommendation services (e.g. Stumble).

[1] This would have been possible on the old delicious site but delicious had severe throttling in place to prevent crawling this data. Now it appears avos has removed the list of 'co-bookmarkers' entirely from the website.