It's onswipe, and they've just done a deal with wordpress.
I find it really jagged on scrolling and generally annoying enough to be distracted from the articles. Also, what looks like a link to turn it off and go to the old site doesn't work.
I had the same issue. You can't even read the bottom of the post on an iPad. I eventually ran it through Readability just to be able to read the entire post.
