Hard disks are on the way out, said the Flash memory makers at the Computex IT show in Taipei. Capacities are already 64GB for top-end Flash drives, and the technology is set to revolutionise computer design.

Well, perhaps. As soon as I heard that hard disks were facing extinction, I thought: “What, again?” In the early 1990s, makers of magneto-optical drives said the same thing. The big two obstacles were that the new kit was slow and expensive – and Flash media is certainly very pricey.

Looking back, it seems laughable that magneto-optical drives were ever considered for anything more than archiving. But consider the current popularity of LCD monitors. In the early 1990s, it was also claimed that LCD displays would take over from CRT monitors on the desktop. How I scoffed: LCD technology was slow and expensive, while cheap CRT was, after all, the de facto standard.

You can learn three lessons from this example. First, I’m hopeless at guessing the Next Big Thing. Second, price and performance may be irrelevant if you offer other desirable benefits. Third, de facto standards can change on a whim.

Real standards – de jure standards – are established by industry bodies, are generally based on freely published technology, and tend to benefit the industry as a whole. A de facto standard, on the other hand, is often based on jealously guarded technology and managed with the sole aim of making money for its owner.

But compare Adobe’s SVG format (open, free, de jure) with the Flash or PDF formats (only partly open, commercial, and de facto). PDF is a somewhat complicated example, since Adobe has spent years promoting the format and has published the spec to encourage third-party developers to work with it, while at the same time trying to maintain its ownership. The situation is that de jure standards have now been established for PDF export settings, though PDF essentially remains private property.

Given that Adobe wants PDF to take over the world, it’s no wonder that Microsoft was perplexed by its demand that the export-to-PDF feature be removed from the shipping version of Office 2007. Adobe fears that putting PDF into Office could make it so de facto that sales of its own Acrobat line could suffer.

So we learn a fourth lesson: de facto standards are not free from commercial interference. Adobe’s attitude risks putting firms off the PDF/A standard for document archiving, and so could ultimately rebound on it. Microsoft will probably be happy if its own file formats remain the preferred de facto standard for documents.