I think the title is misleading. If I'm not mistaken it's not actual infinite scrolling, the only change is the search bar and search tools remain in a fixed position. It's a nice change.

>The new interface seems to set the stage for a fluid design that removes pagination and replaces it with infinite scrolling.

The key phrase in the article is "setting the stage". Google hasn't switched to infinite scroll yet, but with a fixed header it seems most likely for them to do so soon.

I haven't seen it in action, but from what I saw in the video, it was actual infinite scrolling - the pagination controls got replaced with 'second page' content after scrolling down.

My guess is that the pagination controls are there to accomodate people with JavaScript disabled.

My favourite way to combine pagination with infinite scrolling (for reading, at least) is to use columns - the line after the bottom of the first column is at the top of the second column, and scrolling down scrolls all columns along line by line. Scrolling left and right snaps to columns, and scrolling right by one column is equivalent to scrolling down by one page. Scrolling right by one page is equivalent to scrolling down by page_height (in lines) times page_width (in columns).

Can you give an example? I have disliked all the column-based screen reading formats I've ever seen.