If the author can't make it so that it tells me, on page 1, how to get to page 2, then I wonder about how credible a source they are for anything to do with UX.
The slides were initially made to complement my talk at Front Trends 2010, so it wouldn't make much sense in that context.
No, not in that context. But maybe when you posted them on the internet, maybe that's a different context? And being a CSS expert, you were quickly able to add the sentence "Use the arrow keys" in a nice, small, print at the bottom. Right? Being an expert?