Update at 5:30 AM Pacific on March 2, 2010: I mistakenly reported that Facebook has moved from MySQL in favor of Cassandra. According to a credible source familiar with Facebook's systems, this is not the case. Indeed, you can actually follow "MySQLatFacebook" on Facebook. I apologize for the error and am glad to see MySQL is still in active usage at Facebook.
Open-source software has hastened the evolution of Web applications as it drives out the inefficiencies and costs of proprietary software to enable companies like Google and Twitter to scale. But it's not just proprietary software that is feeling the squeeze:
Can open source hope to compete with itself?
As one example of this trend, Informationweek reports that Twitter, Facebook, and Digg have all dropped MySQL in favor of Cassandra, an open-source data management system. Cassandra, an Apache project, is part of the so-called "NoSQL" movement, which includes other open-source projects like MemCacheDB, Hadoop, and CouchDB.
It's not a slam on MySQL, which remains an excellent database for a wide variety of uses. But it's an indication of how fast the open-source world moves, and how fickle its clientele can be.
It's also a sign of just how hard and fast one must compete to keep up with open-source projects, especially on the Web.
And it's not just NoSQL vs. MySQL.
Mozilla's Firefox, for example, ruled the open-source browser roost for years, but is starting to get real competition from Google's Chrome, an alternative open-source browser.
In the mobile computing world, users are spoiled for choice with various permutations of Linux, including Android and MeeGo (formerly Maemo and Moblin), vying for manufacturers' attention and routinely replacing each other as they compete for prominence.
As tough as it is for the open-source world to compete with itself, consider the proprietary competition that has been cast by the wayside. Sun used to position itself as the center of the dot-com revolution, only to find itself upstaged by the Linux crowd.
And as much as MySQL may be feeling the pinch of NoSQL competition, at least it's still in the game. Oracle has never been a serious contender for running Web applications at scale, while Microsoft struggles to make its SQL Server technology and pricing sheet fit (not that it's not trying).
Could this be a sign of things to come?
Absolutely, though there remains comparatively safer ground for old-school proprietary software vendors. It's called the enterprise. Enterprise IT is somewhat less concerned with innovation and more concerned with risk avoidance, and so less inclined to hop on the fast-moving open-source innovation track.
Eventually, however, yesterday's Web technology will find its way into tomorrow's enterprises, which will benefit from the furious pace of experimentation the Web companies are driving with open-source software.
For now, enterprise IT vendors can lead a somewhat sheltered existence, one not available to open-source projects that must compete vigorously to keep up on the Web. But it won't last forever.