"In five years, we'll see some big name corporations switch to Google Apps," Madden says, noting that his firm actually uses it currently for e-mail and collaboration. "It's great, but what are the applications that actually make corporations go around? There are a lot of corporations that use very customized applications, and probably five of them will be covered by Google Apps. It's not going to make a big dent in a typical enterprise."

Instead of typical office applications, experts say the sweet spot for online applications like Google Apps is in collaboration, especially as more organizations become virtual and distributed.

"For the most part, people don't need Google Apps even today -- everybody has Office on their computer," Gaskin says. "But where it makes sense is for online collaboration, with tools like HyperOffice."

As an example, he says he knows of a wine importer with employees and vendors scattered across 23 time zones. "It uses HyperOffice to store documents, share calendars and share overall information. Collaboration is becoming much more important, and I see a lot of those applications moving to the cloud."

Attacking the online/offline problem

A big problem, however, for applications such as Google Apps and HyperOffice that run in the cloud is that they have limited offline capabilities. Although high-speed Internet access is becoming more ubiquitous, there are still places where a connection can't be made, and users can't work.

"Every knowledge worker or advanced user is going to need offline capability," Madden says. "Maybe someday bandwidth will be truly ubiquitous, even in the subway and airplanes and the middle of the desert. But that will be a while. It won't be in five years."

Google is attempting to tackle the problem with its Google Gears API, which lets developers create offline capabilities for their online applications. Similarly, Adobe is offering Adobe AIR, which enables Internet Flash-based applications to work offline. And finally, Microsoft offers Silverlight, which does the same thing for Internet-based .Net applications.

"People say Google Gears, AIR and Silverlight all compete against each other, because they all let rich Internet applications run online and offline, and this will be the new battleground. Whoever wins this is going to win the next application architecture battle," Madden says.

Right now, he says Microsoft has the advantage because Silverlight uses common tools, such as Visual Studio and C#, while AIR requires knowledge of ActionScript and Gears requires high-level Java programming knowledge. "The majority of business applications today are Microsoft applications written on the .Net platform," he says. "And Silverlight will dovetail right into that. Google Gears won't make a dent in the corporate world, but Silverlight could."

And this online/offline dichotomy is a problem not only for rich Internet applications, but it also affects desktop virtualization scenarios like VDI, which also require some kind of network connection.

For its part, VMware recently demoed what it calls VDI Offline, which enables users accessing their server-hosted VDI virtual desktops to take them with them when they disconnect from the network.