In about 1990 I was shocked to discover that Intel ships software products with no warrantee. They do not even warrant that a program will work if used in the routinely expected way. Their position is that there is no "expected way" to use a software product, and what one person thinks is a natural use, a team of 100 testers may never have noticed. And when several software products interact (by plan or accident) there's no telling how they might affect each other.
It took me awhile to see it, but I believe Intel was right. Which brings us to two of this week's remarkable news stories.
First, a systems internals guru named Mark Russinovich carefully analyzed what happens when you insert a Digital-Rights-Management Sony audio CD into your computer. These CDs intend to restrict you from making what Sony regards as illegal uses of the music. He found that the CDs install what some might call "malware" often used by hackers to control systems. You can read about his discoveries here, in detail. In brief, the software modifies the Windows operating system at a low level in order to conceal files on disk and programs that are running, from all but the most astute users. Sony's not the only music publisher doing this kind of thing, and it's going to be a big story, expecially since Sony apparently does not get your permission to modify your system this way (possibly publishable in California by $10,000 per infraction). Worse, their software apparently makes it easier for others to add their own "cloaked" software to your system, once the Sony software's in place. But that's not important now.
Second, there's the company Blizzard, which operates the massively online multi-player World of Warcraft game (aka "WoW"). Blizzard also puts software on your computer to watch and possibly control what you're doing. Their software may fall into the category of Spyware. Blizzard insists its "Warden" software is a good thing. They are trying to prevent you from cheating at WoW by running programs to give you an unfair advantage over people playing manually. You can read about that here. It's not clear whether Blizzard is wearing a white hat or a black hat, but that's not important now.
So what happens if you play Sony's DRM music AND go online to play WoW? Well the Sony software makes it easy for you to cloak your "unfair" programs that give you a gaming advantage so that WoW's Warden software can't see them. There's your unexpected consequence.
Just for a moment, please try to imagine every computer in your home and company running cloaked software like this from fifteen different companies at once to make sure you do nothing illegal. You'd have only a few cycles of CPU time left for yourself. You'd have to buy MUCH more powerful computers. Now that's important.