I just talked with Bob Moul, CEO of the software-as-a-service integration company Boomi, and he's seeing more requests for companies to connect legacy, enterprise EDI infrastructure with SaaS applications.Moul's in a good place to spot how alternative IT approaches are taking shape in businesses, including how well SaaS is meshing with the legacy IT world. Boomi sells an online integration platform, where companies pay a monthly fee per connected instance to link SaaS to other software. About 75% of its business is connecting SaaS apps to conventional on-premises software. The rest is SaaS to SaaS.

Moul offers the example of converting data from a SaaS-based warehouse management system into EDI format for transactions with legacy on-premises software. Sure, someday those legacy apps may move to the cloud and allow app-to-app links, Moul says, but "people have been announcing the death of EDI for a long time."

The other trend Moul sees is "narrow and very deep" apps--ones that do a single task very well, like Xactly's compensation management tool. Again, that speaks to SaaS-to-legacy integration, as people start using those specialty tools then want it tied to an on-premises HR or ERP system. (Here's a closer look at real-world SaaS integration problems.)

SaaS vendors like to have it both ways--playing the renegade "don't tell the IT department" message when it suits the sales cycle, but wanting the legitimacy that comes with fitting into an enterprise IT architecture. The renegade approach is going to be less and less important for SaaS. CIOs don't fear SaaS, and increasingly will make what today are alternative IT approaches central to their strategies. (Salesforce.com just posted 20% sales growth.)