It started as a question: what if I want to present a stream as a series of slides, one for each card? Introducing...
Firstly, when you're on a card detail page (just click the timestamp on the lower right of any card) the earlier / later links now navigate to the earlier / later card.
Secondly, we've introduced keyboard support: left-arrow and right-arrow navigate between the cards in a stream. up-arrow will take you back to the overall stream.
Thirdly, you can toggle between the normal card detail display and a distraction free larger display for presentations with the p key.
We have more planned for presentation mode and a lot more planned for keyboard support, so stay tuned!