Oracle Streams AQ (Advanced Queuing) provides highly scalable database-backed queuing functionality. Does an equivalent feature exist in SQL Server (any version)?
Note: I do not mean simply using a table as a queue, but a specific vendor-provided enhancement to the database platform.
Service Broker. A good intro is here: An Introduction to SQL Server Service Broker. Available since SQL Server 2005. High scale, high performance messaging, built into the SQL Server engine, completely integrated (messages are stored in hidden tables in the DB, the access API is fully integrated into T-SQL language as BEGIN DIALOG, SEND, RECEIVE verbs), supports Activation, message correlation and many more. Is it scalable enough to provide the messaging back bone for MySpace.