Users seem to be ahead of IT when it comes to embracing software-as-a-service (SaaS), according to a new survey.

The Forrester survey of more than 1,000 IT decision-makers in North America and Europe found that 16 percent of enterprises had adopted SaaS as of 2007 - an increase from 12 percent the previous year but still a small minority.

Actual enterprise adoption of SaaS might be much higher, though, because business units often deployed hosted applications on their own, sometimes seeing it as a way to free themselves from relying on IT, said Forrester analyst Liz Herbert.

"A lot of SaaS is still deployed at the business unit level. [IT executives] might not necessarily be aware of all the SaaS that's deployed in the organisation," Herbert said.

While 16 percent of Herbert's survey sample were using or piloting at least one SaaS application, another 46 percent were planning a pilot or interested in having one, according to the Forrester report, Competing in the Fast-Growing SaaS Market. About 37 percent had no interest in software-as-a-service.

Executives who weren't interested in SaaS most commonly pointed to concerns about integration, total cost, lack of customisation and security. Application performance concerns and vendor lock-in were also preventing some enterprises from using SaaS.

But the number of IT executives who have at least some interest in hosted software indicate to Herbert that IT involvement in SaaS projects is poised for a big increase.

"It's not like that 84 percent [that haven't deployed SaaS] is sitting there and saying 'there's no place for software-as-a-service in our organisation,'" she said.

The hosted software market was growing more mature, with extensive customisation and integration into an enterprise's internal systems, she noted. And whereas SaaS applications are typically for general business tasks like human resources, there are now hosted applications designed specifically to help IT staffers manage an enterprise's technology, she said.

Still, the most commonly used SaaS tools were for human resources, collaboration and CRM. Nearly half of SaaS users were using HR tools, 38 percent were using collaboration software and 36 percent were using CRM.