Robert X. Cringely, via Status-Q:
One of the cheapest Linux computers you can buy brand new (not at a garage sale) is the Linksys WRT54G, an 802.11g wireless access point and router that includes a four-port 10/100 Ethernet switch and can be bought for as little as $69.99 according to Froogle. That's a heck of a deal for a little box that performs all those functions, but a look inside is even more amazing. There you'll find a 200 MHz MIPS processor and either 16 or 32 megs of DRAM and four or eight megs of flash RAM -- more computing power than I needed 10 years ago to run a local Internet Service Provider with several hundred customers. But since the operating system is Linux and since Linksys has respected the Linux GPL by publishing all the source code for anyone to download for free, the WRT54G is a lot more than just a wireless router. It is a disruptive technology.
A disruptive technology is any new gizmo that puts an end to the good life for technologies that preceded it. Personal computers were disruptive, toppling mainframes from their throne. Yes, mainframe computers are still being sold, but IBM today sells about $4 billion worth of them per year compared to more than three times that amount a decade ago. Take inflation into account, and mainframe sales look even worse. Cellular telephones are a disruptive technology, putting a serious hurt on the 125 year-old hard-wired phone system. For the first time in telephone history, the U.S. is each year using fewer telephone numbers than it did the year before as people scrap their fixed phones for mobile ones and give up their fax lines in favor of Internet file attachments. Ah yes, the Internet is itself a disruptive technology, and where we'll see the WRT54G and its brethren shortly begin to have startling impact. ...
If you have a WRT54G, here's what you can use it for after less than an hour's work. You get all the original Linksys functions plus SSH, Wonder Shaper, L7 regexp iptables filtering, frottle, parprouted, the latest Busybox utilities, several custom modifications to DHCP and dnsmasq, a PPTP server, static DHCP address mapping, OSPF routing, external logging, as well as support for client, ad hoc, AP, and WDS wireless modes.
If that last paragraph meant nothing at all to you, look at it this way: the WRT54G with Sveasoft firmware is all you need to become your cul de sac's wireless ISP. Going further, if a bunch of your friends in town had similarly configured WRT54Gs, they could seamlessly work together and put out of business your local telephone company.
That's what I mean by a disruptive technology.