Just try creating a definition of cloud computing that's broad enough to encompass all its permutations and narrow enough to provide technical guidance on how to get one cloud talking to another.
At least three years (although possibly eight, arguably 11 and somewhat untenably, one) after the phrase "cloud computing" was first used to describe on-demand computing services, nearly every conversation with experts involves defining what you both mean by it.
"At Burton Group it took a meeting where all the analysts were present over two days to come up with a definition, and it ended up being very small, so it could encompass everything," according to Chris Wolf, analyst at the Burton Group.
"Not always, but usually you're talking about either software as a service, infrastructure services, or running an application on someone else's cloud," says James Staten, analyst for Forrester Research. "Within that there are a lot of variations. There are no standard pricing models, standard offerings, definitions of terms--if enterprises are going to consume this, they have to know what they're getting. There have to be things that will be the same from cloud to cloud."
Source: CIO