Hi Nima, Dave,
About three months ago we started working on an integration with Blackboard using their building blocks. First it took quite a while to get around the limitations of Bbs API. Then we discovered that in different platforms (Windows, Solaris, etc) the API behaved a bit differently, which added quite a bit of pain to the process.
Additionally, if you require a simple data table to store whatever variables you need, guess what?, you can't use the same datamodel as Bb! So you have to resource to quite a few shortcuts and workarounds.
Comparing between Bbs building blocks and .LRN, I would prefer .LRN's /api-doc any day as it wins hands down.
.LRN is simple, robust, scalable and very extendable. Where as Bbs, well...
Ernie