Tim Bray claimed in a keynote last week that "XML and open source are the parallel outcomes of a single trend."

Following up on this thought in his blog, "Ongoing," he wrote:

"I don't think that the argument is that subtle or difficult. In the old days, when you went out to get IT infrastructure, it was a black box and all you worried about was how much it cost and what its features and UI were like. If you asked how the software worked, or where the data was or what its format was, you were told not to bother your pretty little head."

"These days, interoperation and integration are everything. You'd better have open interfaces, open networks, open services; that is, open data. Which in practical terms usually means XML."

Bray's argument is, as he said, simple. Once the world's IT customers realize that they've basically won in their quest for what Bray called "unrestricted visibility into their own data," they're going to start wondering why they can't see inside the software they're betting their business on.

"Which is to say, exactly the same forces that are driving the world to open data in general and XML in particular are driving us towards open source."

Bray ended, with charactertistic candor: "Secret-source software probably isn't going away, but in an increasingly open world, it looks weirder and weirder."

"I am not saying that users should stop paying for software," he added (Bray now works for Sun Microsystems, though his private blog and Sun are not to be confused), "or that companies should stop planning to make money from it."

"My employer is in the mist of launching Solaris 10, and it's going to be Open Source and free to download, and we sincerely hope to make a lot of money from it. But the days when the recipe for success included wrapping the engineering in a veil of secrecy, those days are gone."