Mark Baker, always a source of informative links, points to a post by Steve Jones who says that resistance is futile and you will be assimilated.
Yes, and the sun revolves around the earth, Steve.
I know one of the four companies Steve mentions up closely and have struggled with getting my .Net client working against some of their web services. Nothing major like schema madness, just the sort of little incompatibilities which sometimes let you hit a wall. But my point is, now that we have it working, the guys maintaining the backend database are going nuts with the load some developer PCs put on them. Because it's just pieces interconnected with some shoe laces and no one has the complete picture and thought perhaps a little about the cacheability of things.
Now, of course this all can be fixed. But some little app which replicates the (slowly changing) database into a couple of XML documents served by Apache would do the job much more reliable, stable, scaleable and magnitudes cheaper. And I advise them to do so. Let's see.