Ask HN: Any ideas as to why Google changed search result margins?

Since we don't have access to our data, and since it took them a very long time to do this, I'd guess that the reasons are more subtle than we could practically guess. It probably increases their profitability per page by some tiny fraction, which is big money with their volume.

Well thought out gutters can make a big difference to the readability of a page, but that generally is only a big factor when it comes to pages with lots of data crammed into multiple columns; not something you’d assume would be a problem on a Google results page. My best guess is that (like the aforementioned shades-of-blue incident) they did a whole bunch of user testing that suggested that the usability and probably profitability of the page went up by a couple of percent with that precise amount of extra margin.

I have no idea. If they don't change it soon I'm moving over to bing for keeps.