I'd have to disagree, even though I seek recip links all the time myself. I do think they are "unnatural" from the search engines' perspective. They want links to be a kind of vote for the site being linked to. In that analogy, it would be akin to me giving you a quid pro quo in return for your vote. Not exactly natural. Who knows, really, what the engines are looking at? I'm just speculating... could be way off base.