For many IT shops, nothing strikes fear as deep in its heart as the notion that a new technology will be as alluring to users as Excel, which in many organizations has withstood every attempt at being controlled at all by IT.

Perhaps one of the best descriptions of Excel may be the "cocaine of finance users." Once they - or all different types of users for that manner- get a taste for it, there is no turning back.

Just ask business intelligence vendors. They spent years of development and millions of dollars trying to create BI software and tools that would replace Excel, which they billed as being a tenable way that many companies were being run with employees showing up at meetings with multiple versions of the truth based on the data they hoarded in their own "spreadmarts" instead of using a verified, centralized system. While the notion of eliminating the thousands of spreadsheets users had in place outside the control of IT resonated with IT itself, users would have none of it.

After the realization that users were wedded much more tightly to their beloved spreadsheets than anyone knew, many BI vendors changed their tunes and began marketing tools that linked with Excel instead of trying to replace the venerable Office tool.

Thus, it likely was unsettling - to say the least - for those IT managers in the audience at a session last Wednesday at the O'Reilly Web 2.0 Expo in San Francisco to hear John Musser of Programmable Web, a company that tracks Web mashups, theorizing that enterprise mashups may wield their way into the enterprise much like Excel did.

Enterprise mashups, which took center stage at the Web 2.0 Expo, are applications that can quickly be made by an individuals or a small group of people by ashing together multiple internal or external data sources.

"Will this be the Excel of this era? It is something that business can control and use to get things done," Musser noted. "For IT it raises a bit of a conundrum. Enterprise mashups exist as a confluence of a lot of Web 2.0 technologies coming into the enterprise. They are all coming into the enterprise at different rates, but one way or another they are all going to arrive there. Web 2.0 could come in the side door the same way that instant messaging and other things have come in before."

And the main reason for that, he noted, is because users have a long laundry list of projects they need to get done that typically fall below the radar of IT, which is usually distracted with much bigger problems like keeping the lights and pipes on and developing massive back-office applications.

Mashups allow users to get this laundry list of needs met more quickly without the delays or costs commonly associated with going the normal route through IT.

Take, for example, a group at Audi who went to its IT department asking for an application to extract data automatically from 20 Web sites that they were checking manually. The IT department said it would take US$500,000 to build the app. But, the group at Audi turned to Kapow Technologies to use its mashup server and instead build it on its own in four days, Musser said.

But, Musser acknowledged that in addition to the potential of pitting business users against IT, mashups do create challenges for companies. First, this is an immature marketplace, and many vendors might not be offering service level agreements for their mashup offerings.