Never is a long time
(Disruptive Technologies and the Web)

Steven Pemberton, CWI and W3C, Amsterdam

Transatlantic sailing ships

Next year is the 400th anniversary of an Englishman, Henry Hudson, working for a Dutch company, discovering the island of Manhattan. Then, and for centuries after, all trans-Atlantic shipping was done with sailing ships.

Hudson and the Halve Maen in the Hudson River

Steam ships

When steam ships were introduced they were not reliable enough to travel trans-Atlantic distances, they couldn't travel far without breaking down, and they were inclined to blow up.

An early steam ship


But steam ships were able to find a niche in lake and river transport, where the distances were short, and where they had the advantage of being able to travel against the wind and on wind-still days.

Once in the niche they could improve reliability until they were able to travel trans-Atlantic.

Once that happened, all shipping switched to steam, and all the companies producing trans-Atlantic sailing ships went out of business; not one survived into the 20th century.

Disruptive Technologies

Steam ships are an example of a disruptive technology, a term introduced in the excellent book The Innovator's Dilemma by Clayton M. Christensen.

Typically, technologies improve gradually and continually over time. These are sustaining improvements. An existing technology fulfils or exceeds the market's needs.

Sustaining improvements


A disruptive technology when introduced is able to do similar things as an existing technology, but has one or more disadvantages that make it less desirable for the existing market, such as higher price, lower performance, lower reliability etc.

A disruptive technology is introduced


If that were all, then of course no one would buy it, but a disruptive technology always has at least one advantage over existing technologies that despite its disadvantages allows it to find a niche, and therefore survive.

A disruptive technology improves to beat extant technologiesWhilst in this niche it is able to improve, typically more rapidly than the existing technology, until it performs equally with the existing technology, or at least sufficiently for the market needs, but with the added advantages that it had that allowed it to survive.

As a result the existing market steps over to the new technology and the old one dies (typically taking the companies producing the technology with it).


There are huge numbers of examples of disruptive technologies.

The book documents many other examples, such as pneumatic diggers, 14 inch disks being replaced by 8 inch disks, being replaced by 5¼ inch disks, being replaced by 3½ inch disks, and the change from mainframe computers to minicomputers to PCs.

One example: 5¼ inch disks

It is difficult to believe that the change from 8 inch to 5¼ inch disk was a disruptive innovation. Compare the two when 5¼ inch disks were introduced in 1981:

8 inch 5¼ inch
Capacity 60 Mbytes 10 Mbytes
Volume 10 litre 2.5 litre
Weight 10 kg 2.75 kg
Access time 30 µs 160 µs
Cost $3000 $2000
Cost per Mbyte $50 $200

Other examples

You can probably identify lots of others examples of disruptive innovations just by thinking of things that have essentially disappeared:

LCD Screens

Never is a long time

You probably think that those examples of disruptive technologies are obvious. But spotting them with hind-sight is easy.

Typically many people only see the disadvantages of a new technology.

I have heard so many times "xxxx will never replace yyy because ..."

Future examples

You may be even to guess at some future disappearances:



Remote control

Solid-state disks

Flash disk prices

In 2005 a 1G USB stick cost €80. Here is the price development in the last year:

USB Stick price development


The Web as Disruptive Technology

The initial Web was small and slow and almost no one used it, but it quickly grew to threaten many existing technologies.

And it continues to threaten radio, TV, publishing in general, and on and on.

Technologies within the Web

The Web is built out of and on top of many technologies.

Technologies within the Web

It is these technologies I now want to focus on.

i will in particular focus on document technologies.

What are the market needs?

Market needs

Note that an extant technology may become unsuitable because the needs of the market change.

This is then an ideal moment for a disruptive technology to move in.

Case study: CSS

What are the advantages of CSS over plain formatted HTML?

Why did we want CSS in the first place?

Separating Content and Presentation: Author Advantages

Separating Content and Presentation: Webmaster Advantages

Separating Content and Presentation: Reader Advantages

CSS was not a disruptive technology

CSS was a sustaining improvement in Christensen's terms.

It made existing HTML better.

Why I think CSS is at risk

While it was initially a big improvement over what we had, it has improved little in the last decade.

It doesn't address essential styling issues like reordering content.

It offers little in the way of definable behaviours.

Its graphical possiblilities are very limited.

Stylesheet 1980s style

The analogue clock here is produced by an application of a stylesheet on the raw clock data:

Cloks by stylesheet


A new technology on the way is XBL (XML Binding Language)

Implemented in Mozilla

An up-coming W3C standard

Implemented in other systems as well.

Stylesheets 2008 style

This is using SVG as stylesheet, by applying it with XBL. The clocks are just strings like 11:30:00.

Closks with SVG

Case study: Forms

HTML Forms have been a great success.

But after a decade of experience, we know how they can be better.

XForms was designed as a replacement for HTML Forms. However, because of its general design it can do much more.

In fact since it has input, output, and a processing model, it is an application language.

The advantages of XForms

Much easier to write applications.

Accessible out of the box

Device independent

Ease of writing

Google maps is 200k+ of Javascript.

Someone wrote a pilot study of Google maps in XForms: It was 25k of XForms.

Google maps in XForms

Ease of writing

A company that makes room-size machines, with complicated user interfaces normally uses 30 people for 5 years to build the user interfaces.

When they tried XForms, they did it in 1 year with 10 people!

Accessible and device independent applications

An implementor demonstrated the same form running on a PC, a cell phone, a voice browser, and even as an IM buddy.


Not widely implemented

Initial learning curve


Here is a taste


The authoring savings make XForms a sure-fire success when it is adopted.

A new implementation of XForms called Ubiquity which will run in all browsers iss ound to make it more popular.


Christensen's book has changed the way we look at the world, and how we evaluate technologies.

It can show up technologies that seem unimportant, but allow us to analyse their chances of success