What is the "Chaos" Isolation level and when should it be used? ADO.NET documentation shows the possibility of setting the transaction level for a SQL transaction to Chaos. It sounds unpleasant, but if the feature is there, presumably it has some legitimate use.

The SET TRANSACTION ISOLATION LEVEL command in BOL (ah! see, I can use google and BOL) nothing seems to be named "chaos" and ADO.NET does have 5 modes that match up nicely to documented levels in addition to "chaos"

What or who is this Chaos level for? (And why does it have an unfriendly name?)

Refs:
The ADO.NET enum
You can't use it against SQL Server.

It was in DTS: 


Chaos Isolation Level In SQL Server - SQL Server Code,Tips and Tricks, Performance Tuning


And is in SSIS:


DtsContainer.IsolationLevel Property - MSDN


More references, originally added by Nick Chammas in a comment:


Rollback is not supported
SQL Server and Oracle don't support the chaos isolation level