For example, a while ago I read an article that talked about peanut allergies being less prevalent/severe in Europe than the US, and Europe having more cases of other allergies (like apple allergies). It then went on to talk about different pollens that may react with our bodies to trigger certain allergies. I can't recall how long ago I came across this, or where (could have been HN, Slashdot, Digg, etc). I've also not been able to put together a search to turn up this article in Google. Had I been better about bookmarking, maybe I would be able to find this article even if it took a brute-force search through all of my bookmarks.