“THE promotion of network neutrality”, wrote Tim Wu of Columbia Law School in a widely read paper a decade ago, is about “preserving a Darwinian competition among every conceivable use of the Internet so that only the best survive.” He thus not only coined the label for one of the most controversial of internet-policy issues, but correctly predicted that it will be a difficult one to sort out. On February 26th America’s Federal Communications Commission (FCC) will have a go at regulating, and defending, network neutrality, by taking the radical step of reclassifying internet access as a utility. But what is it? For much of the internet’s history the network has been neutral by default, thanks to its technical rules, which are blind to the type of data being handled. This more than anything explains the disruptive (and Darwinian) power of the internet: network operators could not play favourites among the packets of data they were transmitted, and startups didn’t have to ask them for permission to build innovative services. But new technologies, like the inelegantly named “deep packet inspection” (DPI), now allow network operators to identify what kind of traffic they are funnelling through. At the same time new forms of traffic are increasing in importance and generating calls for better traffic management: Netflix, the video-streaming service, now accounts for a third of peak traffic in America, for example. To handle this data flood, telecoms firms say, they need to build bigger pipes and charge the likes of Netflix to use them.

Most observers agree that in some form or another the concept of neutrality with respect to data should be enshrined in law. But they cannot agree on the exceptions to the rule. Network-neutrality purists insist that there should be none. Rent-seeking network operators would exploit any loopholes, they argue, and rather than investing in DPI or such things, telcos should simply add capacity. Others are not so sure, and would accept several exceptions: emergency and health services, for instance, should always enjoy priority. Some wonder why exactly bandwidth-hungry offerings such as Netflix should get a free ride. Unsurprisingly, positions in the debate are often based on interests and ideology. Producers of digital content, for instance, often argue in favour of strict network-neutrality rules, which make distributing their wares easier. Libertarians think the internet, as most other things, should simply be left alone.

Given this cacophony, it comes as no surprise that only three countries—Chile, the Netherlands and Slovenia—have so far passed strict network-neutrality laws, whereas most others have opted for softer rules. And it is unlikely that the principle will ever be set in stone: as technology and digital markets change, so will the definition of neutrality. In America the FCC's decision certainly will not end the debate. Lobbying has already begun over how the new rules, whose details have yet to be made public, should be interpreted. And big broadband access providers, such as AT&T and Verizon, are sure to sue: they could live with network-neutrality requirements, but hate the idea that their internet business should be regulated in the same way as their plain-old telephone service.

Dig deeper:

Internet rules are inevitably a work in progress (January 2015)

How best to sort out the network-neutrality mess (January 2015)