Over the next few years, Hadoop reinvented data analysis not only at Facebook and Yahoo but so many other web services. And then an army of commercial software vendors started selling the thing to the rest of the world. Soon, even the likes of Oracle and Greenplum were hawking Hadoop. These companies still treated Hadoop as an adjunct to the traditional database — as a tool suited only to certain types of data analysis. But now, that's changing too.
via NoSQL databases