Yahoo! Labs! Advertising Sciences has built a general-purpose, real-time, distributed, fault-tolerant, scalable, event driven, expandable platform called S4 which allows programmers to easily implement applications for processing continuous unbounded streams of data.
I cannot say it enough: Yahoo! is kicking ass again. After hearing about Google Caffeine, many were quick to announce the death of MapReduce/Hadoop . But Yahoo! was busy at work open sourcing real-time MapReduce.
Original title and link: Real-Time MapReduce (NoSQL databases © myNoSQL)