Though I have not come across this myself, I’ve noticed a couple of reports of Google experimenting with a new format for there SERPs.
Having recently spoke of the importance of page speed and validated HTML, it would certainly seem to me that Google are focusing more on mobile search. Whilst obviously these experiments have been noted on desktop browsers, infinite scrolling has been apparent on a number of my iPhone apps and does make browsing a lot easier:
My initial reaction to seeing these new SERP layouts is that Google are looking to make searching easier on mobile devices. What this means for CTR and page 2 rankings remains to be seen but it certainly seems, if you’re into that sort of thing, to be an interesting development in search - particularly when it comes to page 1/page 2 CPC bids! (but I’ll leave it to one of our PPC team do a blog post about that)