O'Reilly's Deal of the Day today offers multiple benefits and is detailed at http://oreilly.com/store/dd-jpn.html. The obvious benefit to software developers is 50% off the price of their DRM-free ebooks that are available in numerous formats. As I have highlighted before and as their page states, "Ebooks from oreilly.com are DRM-free. You get lifetime access, multiple file formats, and free updates."
O'Reilly has made this deal even more attractive by providing a benefit to the relief effort associated with the recent earthquake and tsunami in Japan. Their page describes this: "O'Reilly, No Starch Press, and Tidbits will donate all revenues, less author royalties, from today's 'Deal of the Day' sales to the Japanese Red Cross Society."
The Deal of the Day page for today shows that the promotional code for this deal is DDJPN. Note that this deal applies to videos in addition to ebooks.