CK tipped me on this.
The British Library has created an incredible multimedia site dedicated to the Shakespeare quartos, for which they produced full, paginated scans of their 93-copy collection of the 21 plays printed before 1642.
Here’s a sample image from the 1622 first quarto of Othello (click to enlarge):
Excerpt from the “how to compare the texts” overview:
You can view the British Library’s copies of Shakespeare quartos separately or you can compare any two copies. If you choose to see one copy at a time, you will get two pages on the screen as you would if you had the book open in front of you. To read the text you may have to enlarge the image by clicking on it or using the enlarge icon.
Elizabethan and Shakespeare scholars are no doubt having to change their pants over this project, and I would imagine cultural critics are going to be interested as well. The British Library has also constructed a similar site for The Gutenberg Bible, where you can compare their paper and vellum copies of the 15th century manuscript that completely and forever changed Western literacy. The scans here are absolutely breathtaking:
And as incredible as these Shakespeare and Gutenberg projects might be, they pale in comparison to the Library’s “Turning the Pages” section. Shockwave and Flash technologies allow you to virtually thumb through some truly amazing texts like DaVinci’s sketchbook, King George III’s personal copy of Blackwell’s Curious Herbal, Vesalius’ De Humani Corporis Fabrica, Sultan Baybars’ personal Qur’an, a 15th century copy of The Golden Haggadah, and last but certainly not least The Diamond Sutra, printed on a Chinese scroll dating from 868 (and, thus, the world’s oldest printed work). Because these virtual texts use Flash, the pages really turn (the scrolls on the Diamond Sutra actually scroll); a virtual magnifying glass, page-by-page descriptions and audio tracks are also included.