agent_x - 12:59 pm on Apr 27, 2011 (gmt 0)

patc, that's what I think - I think they must have the technology to render the page to determine what elements are above the fold and what are below and so on, and I think they also use this technology to render the preview thumbnails you see on the search page, which are downloaded post-load. But if someone knows for definite that is not what they do I'd be glad to be corrected.