Amazon has sued Discovery in a Delaware court, alleging infringement of search engine and recommendation patents, and the etailer has also countersued over Discovery’s claim of infringement on their ebook patent.WSJ Amazon has also released a new version of their Kindle iPhone app, which adds some of the basic functionality suspiciously missing from the first version (leading some to view it is a crippled reader). The new version allows reading in landscape mode, and lets users “pinch to zoom images in books” and “tap on either side of the screen or flick to turn pages.”