Purple Leaf [NPE] filed suit against Amazon over a patent related to online payments and receipts for electronic transactions.  This is the third suit filed by Purple Leaf since the end of May. Defendants named in the two prevuiys suits include Citigroup, American Express, Fiserv, Google, eBay, JPMorgan Chase, and SAP. Purple Leaf appears controlled by the inventor of the patent-in-suit, which has a 1999 priority and was directed to Internet based payment of parking tickets. 7/25, Eastern District of Texas, 6:2011cv00377.