The recent suggestions that Software as a Service (SaaS) is likely to become more popular amongst enterprise users is probably good news for the users themselves – the fact that a growing number are starting to think that way means that they are likely to be ready the SaaS surge that may be coming.

For many of them, that surge is likely to be thrust upon them whether they like it or not. With the likes of Microsoft, Google and Yahoo already spending money like there is no tomorrow on building huge datacentres, it is going to be an increasing range of SaaS services that will fill up the capacity currently being installed or in planning. And there is a lot of capacity going in. Google is already well-known for the constant streams of servers and associated kit it has been installing. Microsoft is also in on the act, with recent announcements of new datacentres in Dublin and Chicago – each at some $500m a pop.

Though it is still often perceived as the new Verb for finding information, Google is arguably the biggest SaaS provider by a country mile, and is only going to get bigger. Its moves into areas such as personal productivity tools also moves it closer to more obvious business applications as well. It can only be expected to move further in that direction – without forsaking its individual consumer users, of course – with more acquisitions of SaaS providers in the business space to join the likes of Urchin and Postini.

Microsoft, while trying hard to catch up with Google in the consumer SaaS market with Live, already has the potential of a serious head start in the business sector of SaaS, not only in terms of its applications suites but also their penetration into the marketplace. And with its acquisition of Softricity it has some technology that could help deliver those applications through a SaaS infrastructure.

Now, to digress just a bit, let us assume that all these vast datacentre resources go purely to servicing the immediate needs of consumers. It may have less immediate impact on enterprise users, who might then see less need to take up SaaS as a front line delivery vehicle. But that would be a serious miss-reading of the runes. What would happen is that a vast army of consumer users will be spawned that is fully expert at exploiting SaaS delivery methodologies, without even knowing it. Any consumer business that then cannot service customers in that way will lose out, probably big time.

In practice, however, that is unlikely to be the scenario, particularly where Microsoft is concerned. For the Big M, business users are still big business, and not something to let slip away without a fight. So offering a SaaS delivery capability, both direct through Live and indirectly through its many levels of business partners, is going to be important.

In fact, now that the company is investing big-time in datacentres it is not difficult to predict the commensurate marketing push. Business users should expect to see Microsoft start to offer some very attractive deals on moving their infrastructure requirements away from onsite facilities and onto a Microsoft hosted service.

And for the smart cookies amongst the CIO community, there could be good mileage to be had in taking one up. Getting the right price terms, over the right time period, with the right Service Level Agreement, all coupled to a Microsoft backside to kick if it doesn’t work well, could prove a tempting prospect to early adopters. It could also be just the kicker that SaaS actually needs to move beyond the status of `nice idea in theory’.

A few weeks ago came the news that VMware, already well established as the poster child of enterprise server virtualisation, was extending its reach down into the small and medium-sized business world. There is a sub-text to this announcement, however, that opens up the world of Software as a Service (SaaS), not only to the small business user but also to their enterprise equivalent – the small department. Indeed, it has the potential to open up SaaS to major enterprises in the same way they grew to love Linux – by departmental stealth.

SaaS is already getting to be of interest to smaller businesses – as witnessed by the success of offerings like NetSuite, Salesforce.com and many others – but there is still a long way to go for it to have claimed to fulfil its obvious potential. One reason, I suspect, is because there are a large number of potential users with established, legacy applications wondering how they get from where they are to the brave new SaaS world.

`Legacy’ in this context actually means that panoply of applications and office productivity tools that run on Windows. These are not only the staple diet of the small business, either: they are also the bedrock on which most large enterprise departments are built, which means they have the same scope as small businesses to consider SaaS as future delivery option.

As one of the potential stumbling blocks for both parties is likely to be the perceived problem of how they get from the `here’ of on-site applications to the `there’ of hosted, managed SaaS delivery, the ability to re-use existing legacy applications could be just the bridging mechanism they require. With VMware claiming that just about anything that can be run on any x86 architecture can be considered as potentially viable in a small SaaS environment, then much of that fear of doing something new can be removed.

As one of its touchstone little tests, VMware often uses an ancient PC game from the Windows 3.x era, and this has been found to run as an effective deliverable in a multi-tenanted SaaS environment.

Yes, there are likely to be some issues here, not least with seriously non-trivial details such as licence rights on legacy applications in a new environment. But the ability to use VMware to create a small, multi-tenanted SaaS environment re-using existing applications has the potential to provide a very useful start point for not only the small business, but also the enterprise department; and it has often been the case that those departments have been the proving grounds on which significant new developments have been tested.