4.6 Case study 1: the second wave of innovation – the graphical browser

Mosaic was created in just under three months by an undergraduate, Marc Andreessen, and a programmer, Eric Bina, working round the clock. Bina wrote most of the new code, in particular the graphics, modifying HTML to handle images, adding a GIF (graphics interchange format) decoder and colour management tools. Like all good programmers, he did it by adapting software tools that already existed – particularly the UNIX Motifs toolkit – and were freely available. Andreessen's contribution was to take apart the library of communications code provided, again freely, by CERN and rewrite it so it would run more quickly and efficiently on the network. Between them the two wrote Mosaic's 9,000 lines of code (compare that with the 11 million lines of Windows 95), in the process producing the most rapidly propagated piece of software written up to that time.

On 23 January 1993, Andreessen released the first version of Mosaic onto the Net. In a message posted to internet discussion groups, he signalled to the internet community that the software was now available for downloading across the network. Having posted the message, he then sat back to monitor the log automatically kept by the NCSA (National Center for Supercomputing Applications) server as it responded to download requests. Within ten minutes of first posting the message, someone downloaded Mosaic. Within half an hour, a hundred people had it. In less than an hour Andreessen was getting excited email from users all over the world. It was the Net equivalent of that moment when Mission Control says ‘We have lift-off’.

Thereafter the UNIX version of Mosaic spread like a virus through the worldwide computing community. The Mac and PC versions followed shortly afterwards. Within a few months it was estimated (nobody at that stage was keeping precise records) that the downloads numbered hundreds of thousands.

Objective measures of the impact of Mosaic also began to emerge. For example, in March 1993 – just a month after the official release of the Alpha version of the UNIX browser, HTTP traffic accounted for just 0.1 per cent of the traffic on the part of the Net known as the NSF backbone. By September, there were over 200 known servers and HTTP accounted for one per cent of backbone traffic – i.e. it had multiplied tenfold in a little over five months.

Mosaic was not the first browser, but it was the one that captured the market and shaped the future. This was partly due to the fact that it ran on simple desktop computers rather than fancy UNIX workstations. It also had something to do with the fact that it was the first browser that looked like a piece of modern, personal computer software: it had things like buttons and scroll bars and pulldown menus.

But perhaps the most significant thing about Mosaic was that it was designed to interpret a new HTML element – <IMG>, the image tag. In doing so it allowed Web pages to include images for the first time, thereby making them potentially much more attractive to the legions of people who would be turned off by slabs of hypertext.

The addition of the <IMG> tag was an extension to Berners-Lee's HTML and a precursor of the various attempts that have been made since then to extend the standard in various ways. At the time, the decision to extend HTML to handle images alongside text was controversial in some quarters, mainly because image files tend to be much bigger than text files. A full-colour A4 picture, for example, runs to dozens of megabytes.

Interestingly, Berners-Lee was also very critical of the addition of the <IMG> tag. Andreessen recalls being ‘bawled out’ by him in the summer of 1993 for adding images to the thing. The frivolity that the visual Web offered worried its inventor because ‘this was supposed to be a serious medium – this is serious information’. What this exchange portended was the change in perspective that was to fuel the Web's phenomenal growth from that point onwards. Berners-Lee and his colleagues saw their creation as a tool for furthering serious research communications between scientists. The programmers at NCSA were more pragmatic, less judgmental. They knew that the facility for adding images to pages would make the Web into a mass medium.

After Mosaic appeared, the Web entered a phase of explosive growth. The program spread very rapidly across the world. As it did so, the numbers of people using the Net began to increase exponentially. As the number of users increased, so also did the numbers of servers. And as people discovered how simple it was to format documents in HTML, so the volume of information available to Web users began to increase exponentially. It was a classic positive feedback loop.

The fallout from this explosion is clearly visible in the statistical data collected by Matthew Gray at the Massachusetts Institute of Technology (MIT), which show the traffic over the National Science Foundation (NSF) internet backbone broken down by the various protocols.

NSFNET Backbone Usage Breakdown

Date % ftp % telnet % netnews % irc % gopher % email % web
Mar 93 42.9 5.6 9.3 1.1 1.6 6.4 0.5
Dec 93 40.9 5.3 9.7 1.3 3.0 6.0 2.2
Jun 94 35.2 4.8 10.9 1.3 3.7 6.4 6.1
Dec 94 31.7 3.9 10.9 1.4 3.6 5.6 16.0
Mar 95 24.2 2.9 8.3 1.3 2.5 4.9 23.9
Source: www.mit.edu

What this table shows is that in two years, the volume of internet traffic involving Web pages went from almost nothing to nearly a quarter of the total.

The spread of the Web was like the process by which previous communications technologies had spread – but with one vital difference. It's a variant on the chicken and egg story. In the early days of the telephone, for example, people were reluctant to make the investment in the new technology because there were so few other people with telephones that it was hardly worth the effort. The same was true for electronic mail. ‘Who would I send email to?’ was a common lament from non-academics in the early days of electronic mail. But once a critical mass of users in one's own intellectual, occupational or social group had gone online, suddenly email became almost de rigueur.

A great difference between the Web and the telephone was that whereas the spread of the telephone depended on massive investment in physical infrastructure – trunk lines, connections to homes, exchanges, operators, engineers and so forth – the Web simply built on an existing infrastructure (the internet, which itself was built originally on the physical layer of the telephone network). And because the internet was an ‘innovation commons’ in Lessig's sense, with an ‘end-to-end’ architecture, there was no agency which could have stopped the innovation – no gatekeeper who could have argued that sending web pages was not an ‘appropriate’ use of the network.

"Anyone who has lost track of time when using a computer knows the propensity to dream, the urge to make dreams come true and the tendency to miss lunch."

Tim Berners-Lee

4.5 Case Study 1: release of the WWW software and protocols

4.7 Case Study 2: Peer-to-Peer (P2P) networking