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[Nick Carr](http://www.roughtype.com/)'s [column](http://technology.guardian.co.uk/opinion/story/0,,2112850,00.html) in today's Technology Guardian offers an insight into the growing trend for [software as a service](http://en.wikipedia.org/wiki/Software_as_a_Service):

> Google is far from the only computing company laying lots of bricks and mortar. Its arch-rival, Microsoft, is building a mammoth data centre on a former bean field in the farming town of Quincy, Washington. It expects that the site will ultimately hold six warehouse-sized buildings encompassing 140,000 sq m of computer-packed space. Also rushing to build or lease data centres are Yahoo!, Ask.com, Intuit, Salesforce.com and Deutsche Telekom's T-Systems unit, among many others.

Guess who isn’t doing this? Skype, for one. Skype uses a peer-to-peer (P2P) model, which means that calls are routed through our users’ computers rather than going through a central server. Compare this to a product like Yahoo! Messenger, which follows the traditional server model: (hence the need for the big purple blob in the middle)

Decentralised P2P software has several advantages over traditional server based software.

* The number of users can increase without increasing the need for costly centralised resources.
* It can rely on the processing power of users’ computers, since each new user added to the network adds potential processing power.

Maybe Nick hasn’t captured the whole picture when he says

> To be a successful software company today, you increasingly have to worry not just about writing code but about assembling and maintaining big, complex hardware systems.

Or not

Photo by Doc Searls