Nos. 1 to 5

1. 3G broadband

Sure, it's not as good as it could be. And the competing mix of standards-as in UMTS/EvDO (Universal Mobile Telecommunications System/Evolution Data Optimized)-creates compatibility problems. But it wasn't that long ago that one could get Internet access only by finding a Wi-Fi hot spot or plugging in an Ethernet cable. With 3G broadband, smartphones, netbooks, laptops and even mobile offices can get pretty good Internet access pretty much anywhere.

2. 802.11g

The first generation of wireless networking technologies were cool. And if you were just accessing Internet content, they seemed plenty fast. But you could forget about sending large files to other systems on the same wireless network. 802.11g made wireless usable for most networking tasks and helped boost the spread of Wi-Fi to offices, homes, parks and hotels around the world.

3. AJAX

It seemed simple at first-just a set of scripts and standards technologies that were already around for building Web applications. But the mix of technologies that make up AJAX launched a Web revolution, making it possible to build attractive and interactive Web-based GUIs that didn't require extra plug-ins or extensions and that worked well in most modern Web browsers.

4. Amazon EC2

Probably the first real iteration of a cloud-computing platform, Amazon.com's Elastic Compute Cloud is still one of the most popular. Making it simple for anyone to throw a virtual server machine onto Amazon.com's powerful server platform, EC2 changed what it meant to own a server or even run a business: A large number of new businesses don't even own server hardware-their entire operations run on EC2.

5. AMD64

At the beginning of the decade, general-purpose 64-bit computing wasn't looking promising. Intel's Itanium architecture was proving difficult to implement and was generally seen as a disappointment. Instead of taking Intel's rewrite approach, Advanced Micro Devices built its 64-bit platform on existing processor technology, and pushed 64-bit processors into the mainstream.