Although the cloud still has its skeptics, some new research from International Data Corporation (IDC) suggests their influence is going to dwindle — and fast.

Global spending on public cloud IT services is expected to exceed $40 billion by the end of this year, IDC reports. By 2016, cloud spending will approach $100 billion.

Over this four-year period, that represents a 26.4% compound annual growth rate. That’s five times as fast as the IT industry overall, according to IDC.

Which cloud services are going to be the hottest markets? IDC says Software as a Service (SaaS) will “claim the largest share” of cloud services spending over the next five years. Interestingly, however, cloud storage and Platform as a Service (PaaS) will grow faster.

This probably comes as no surprise to cloud providers. Infrastructure as a Service (IaaS) is on track to become commoditized (if it hasn’t already), and cloud providers are recognizing that selling SaaS and PaaS will be more profitable over the long term.

From a geographic perspective, the United States will occupy the largest share of the cloud market, IDC reported. Following closely behind the U.S. are Western Europe and the Asia-Pacific region (minus Japan). But the fastest-growth area for cloud spending? Emerging markets, whose “collective share [will] nearly double by 2016 when it will account for almost 30% of net-new public IT cloud services spending growth,” according to IDC.

They say a magician’s best trick is diverting the audience’s attention long enough to create the illusion that he just pulled a rabbit out of a hat or made a scantily-clad assistant disappear. I’m not quite so cynical to believe that there’s anything subversive about all of the analysis of what SAP’s $3.4 billion bid this weekend for SuccessFactors Inc. means for Wall Street or whether SAP overpaid. But I do think there are some other interesting things to look at besides the rabbit in the hat.

Here’s a quick rundown at some other interesting angles the tech media and blogosphere is exploring.

• Bloomberg pulls no punches: This acquisition is the anti-Apotheker.

SAP AG’s then-chief Léo Apotheker told investors in 2009 that the German company’s homegrown technology was “significantly better” than that of Oracle Corp. (ORCL), which had “not done a good job with acquisitions.”

[...]

[Successors and co-CEOs Bill] McDermott and [Jim Hagemann] Snabe have changed tack at the largest maker of business-management software to do a better job meeting demand for new technologies, such as cloud computing, real-time analytics and mobile applications. The SuccessFactors deal shows SAP’s previous go-it-alone approach to the cloud was lacking, said Thomas Otter, a vice president at Gartner Inc.

“My first reaction was: what took you so long?” Otter said in a phone interview from Heidelberg, Germany, less than 50 miles away from SAP’s headquarters in Walldorf. “This means a fundamental shift in terms of their cloud strategy, which has been rather slow to get off the ground. This is a tacit admission that their cloud strategy was a failure.”

• All Things D says this is the start of a SaaS feeding frenzy, crunching the numbers to speculate on the next M&A target:

The first and most obvious thing that’s going to result from the SAP deal is that speculation will surge about another, similar deal. Already this morning, analysts at BMO Capital have upgraded Taleo, a SuccessFactors rival, on the theory that it is now in play and that Oracle is the most likely buyer. Taleo specializes in cloud-based talent management software, and is about the same size by revenue as SuccessFactors. Publicly traded since 2005, Taleo saw its shares close Friday at $32.96, within 13 percent of its historic high of $37.10, giving the company a market capitalization of about $1.4 billion, making it a relatively easy target for Oracle and its $32 billion war chest. BMO boosted its price target on Taleo shares to $40 from $28.

Another one to watch is Workday, yet another provider of cloud-based human resources software, which last month raised $85 million at an implied valuation of $2 billion as warm-up for an expected IPO next year. It’s on track to do about $320 million in billings in 2011, and is nearing profitability.

Another company that will probably be considered for takeout is NetSuite, the company that specializes [in] cloud-based software for running a business. Trading as of Friday at a valuation just shy of $3 billion, it could be a takeover target, too, though its business is humming along just fine. It’s on its way to closing the year with sales north of $235 million — much of that derives from taking customers away from SAP.

• The New York Times’ Bits blog calls us all back down to Earth regarding how long it’s taken SAP to respond to Oracle’s acquisition of RightNow Technologies. Enterprise customers are not moving as fast on the cloud as vendor marketing machines and frenzied bloggers and journalists seem to be:

After the sales boost, as the plan runs, SuccessFactors is the means by which SAP migrates the data bases of big business over to the new computing world.

This is a long-range plan, and not tomorrow’s work at SAP. And so it is an interesting counterpoint to much of the rhetoric inside the tech world about the speed with which the new paradigm for computing — big data centers accessed over the Internet instead of computing systems run inside a company — will take hold among tech’s biggest customers.

In Silicon Valley, said Lars Dalgaard, the chief executive of SuccessFactors, “There is a lack of understanding of how companies do things, and how lethargic they are about change.”

He added that the existing systems “that tell how a plane lands, that keep a heart beating, you don’t change that quickly.”