A recent Forrester survey apparently indicates that that one out of four large companies plan to use an external provider soon, or have already done so. (The Cloud Storage Strategy blog has a good round-up linking to the original report, a summary of the key points, and various commentators.)

Various pundits are apparently surprised by these results. I’m not. I haven’t been able to obtain a copy of the Forrester report, but from the comments I’ve read, it appears that software as a service and hosting (part of infrastructure as a service) are included as part of the surveyed services. SaaS and IaaS are both well-established markets, with significant penetration across all segments of business, and interest in both IaaS and SaaS models has accelerated. We’ve wrapped the “cloud” label around some or all of these existing markets (how much gets encompassed depends on your definitions), so it shouldn’t come as a surprise to already see high adoption rates.

Gartner’s own survey on this topic has just been published. It’s titled, “User Survey Analysis: Economic Pressures Drive Cost-Oriented Outsourcing, Worldwide, 2008-2009“. Among its many components is a breakdown of current and planned use of alternative delivery models (which include things like SaaS and IT infrastructure utilities) over the next 24 months. We show even higher current and planned adoption numbers than Forrester, with IaaS leading the pack in terms of current and near-term adoption, and very healthy numbers for SaaS as well.