Title says it all really.
We're in the process of entering Moodle for the BETT06 awards in the
UK, and one of the questions is about interoperability: I'm right that
we can't export Moodle activities in any format other than Moodle's
own, amn't I?
Regarding interoperability, as with the whole of Moodle, it's strongly influenced by the community of developers and users. Thus, many import formats are supported, whereas there is little demand for export formats other than Moodle's own. 
The following question import formats are supported:
Aiken, Blackboard, Cloze, Course Test Manager, Examview, GIFT, Hot Potato, Learnwise, Missing Word, WebCT.
According to the 1.5 release notes, the quiz activity module
Blackboard 5.5. course import is also supported.
Moodle supports a range of authentication mechanisms:
CAS, FirstClass, IMAP, LDAP, NNTP, PAM, POP3, Shibboleth.

The following question import formats are supported:
Aiken, Blackboard, Cloze, Course Test Manager, Examview, GIFT, Hot Potato, Learnwise, Missing Word, WebCT.
According to the 1.5 release notes, the quiz activity module
- Allows questions rendered and scored externally (e.g. by mathematical assessment engines) to be integrated seamlessly into Moodle quizzes via the RQP web services protocol
- Is prepared for the handling of IMS QTI questions once web services for these become available
- Has new export types - IMS QTI (2.0) and xhtml
Blackboard 5.5. course import is also supported.
Moodle supports a range of authentication mechanisms:
CAS, FirstClass, IMAP, LDAP, NNTP, PAM, POP3, Shibboleth.
Actually, my post above is mostly about interoperability and not much about SCORM. 
Re. SCORM, please check Bobo's answers to some Very Simple SCORM Questions (a misleading titled discussion!
) As users say, Moodle has one of the best implementations of SCORM - a big THANK YOU to Bobo!

Re. SCORM, please check Bobo's answers to some Very Simple SCORM Questions (a misleading titled discussion!

