The computing cloud solidifies before our very eyes. What used to be a nebulous technological dream with little real-world business impact now drives billion-dollar decisions and big-time acquisitions. Let's take a look at the latest news.

Getting out of the lab
One of the first and biggest names in the digital cloud is (NASDAQ:AMZN), whose Elastic Computing Cloud (EC2) platform even pays tribute to the popular moniker. Well, the EC2 service came out of a two-year beta period last week and added official support for Microsoft (NASDAQ:MSFT) Windows environments.

The new service level agreement gives businesses a guarantee for 99.95% availability (or less than five hours of downtime a year) or they will get service credits back for lost time. Also, the Windows support expands the addressable market considerably. To put the new SLA into perspective, I used to support an enterprise-class Unix environment where system downtime meant losing money every minute. Our systems were scheduled for two hours of shut-eye every Saturday night, or 98.8% availability. That was good enough for my employer, and Amazon's guarantee is about 20 times tighter.

This is great news for nervous IT managers who like the flexibility of Amazon's cloud but were nervous about using a beta program to run mission-critical software. Can't blame 'em for that. Now it's time to get down to business.

Wheeling and dealing
Then again, competition is always great for customers and drives technology leaders to more innovation, lower prices, and ultimately better business. That's why I'm excited to see Web hosting provider Rackspace (NYSE:RAX) throwing its hat into Amazon's ring. In one fell swoop, Rackspace has acquired virtual hosting specialist Slicehost and online storage provider Jungledisk.

Slicehost and Jungledisk will add muscle to Rackspace's existing cloud hosting and virtualization products. A freshly signed contract with content delivery expert Limelight Networks (NASDAQ:LLNW) and Jungledisk's support for Amazon's own storage cloud does the same for Rackspace in the storage space.

The opportunities ahead of this micro-cap company are enormous, especially if it can continue to put pressure on Amazon with new technologies and intelligent acquisitions. Rackspace is one of the leading Web hosts already, but breaking into the entirely separate and much larger market of hosting business applications in a software-as-a-service cloud opens up whole new horizons and revenue streams.

Walking in the cloud
I'd be remiss not to mention Google (NASDAQ:GOOG) here. You already know about Gmail and Google Apps, and how those Web-based software packages may have their sights set on Microsoft's home turf in the business world. Last week, Big G took that battle on the road with the first smartphone powered by Google's Android platform.

Sure, Apple's (NASDAQ:AAPL) iPhone and other handsets support Google Apps too – all you need is a fairly modern Web browser -- but it takes more user effort to get there. And as we all know, convenience is king. But Google's services are better integrated into this model, with YouTube music videos only a click away from the built-in music player and a conspicuous Google Search button right next to your thumb. T-Mobile's (NYSE:DT) first stab at bringing all of this to market will likely be followed by many more models, each building on the triumphs and stumbles of the others. In short, it's a step toward putting Google's cloud directly in your hands.

Just scraping the surface
These are the early days of cloud computing, virtualization, Web 2.0, and service-oriented architecture computing. As those exciting technologies mature, the companies that sell them will become true giants of the software world, if they aren't already. If Google and Amazon can entrench themselves as leaders in the cloud, they'll have solid secondary revenue streams that may one day rival their core businesses of today. Small fry like Rackspace could be the next hypergrowth story, like Microsoft of the 1980s or a certain coffee bar in the '90s.

This cloud certainly has a silver lining. It might even be gilded.

Further Foolishness:

Microsoft is a Motley Fool Inside Value recommendation. Google is a Motley Fool Rule Breakers selection. and Apple are Motley Fool Stock Advisor picks. Try any of our Foolish newsletters today, free for 30 days.

Fool contributor Anders Bylund owns shares in Google and uses nearly every service mentioned today, but he holds no other position in any of the companies discussed here. You can check out Anders' holdings or a concise bio if you like, and The Motley Fool is investors writing for investors.

Stock news, financial commentary, and your daily dose of Foolishness: Get plugged in to the The Motley Fool on Twitter!