That was how I got a free Merriam-Webster dictionary for defining words in read mode.

NPR: Review: Microsoft Office Pricey, But Good Value

Now, you can lock the orientation sensor and pretty much never encounter this issue again (we can't ever really imagine needing to read a text-based book with adjustable font sizes in landscape mode, after all), but it seemed worth mentioning given it goes unchanged since the previous version.

ENGADGET: Amazon Kindle DX Graphite review