I was going to just link to Mike Kavis’ post on the Top 10 Reasons Why People Are Making SOA Fail, but I wanted to added some of my own comments. By the way, he’s talking primarily about IT people, not business people, in the fail part of the equation.
Number 1 reason: they fail to explain SOA’s business value. Kavis recommends (and I completely agree) starting with business problems first, specifically using BPM as the “killer app” to justify the existence of SOA.
He continues with a number of cultural and organizational issues, such as change management and executive sponsorship, then discusses a few of the flat-out IT failure points: not having the skills to actually do SOA (and not getting the outside help required), trying to do it on the cheap, thinking of SOA as a one-time implementation project rather than an ongoing architecture, and neglecting SOA governance.
His final reason for failure is allowing the vendors to drive the architecture:
[T]he vendors promise flawless integration if you purchase all of your tools within their stack. The reality is, they have purchased so many products from other companies that their stacks do not deliver any better integration than if you bought the tools from a variety of vendors.
In the face of recent acquisitions, this could not be more accurate.