Today, Adobe released the public beta version of LCDS 2.6 on labs. I see this as a pretty big release because we now have highly scalable streaming data available over port 80 using the HTTP protocol.

Since BlazeDS was released, we've had the option for StreamingAMF, Streaming HTTP, Long-Poll AMF, and Long-Poll HTTP over port 80, however those implementations were based on the servlet container, which has limitations on threads per user connection. The latest release of LCDS bypasses those limitations, and is significantly more scaleable.

You can download the latest release here:
http://labs.adobe.com/technologies/livecycle_dataservices2_6/

Here's a great comparison of features on LCDS and BlazeDS:
http://www.dcooper.org/Blog/client/index.cfm?mode=entry&entry=8E1439AD-4E22-1671-58710DD528E9C2E7

Here is the LCDS 2.6 Developer's guide:
http://download.macromedia.com/pub/labs/livecycle_datservices/2.6/docs/lcds26_devguide_040908.pdf

Chapter 4 discusses the new NIO server based messaging. Here is an excerpt:

Long-polling and streaming channel support over HTTP are a good alternative to simple polling, and approximate real time push. However, in the previous release of LiveCycle Data Services ES, LiveCycle Data Services 2.5, they relied on servlet-based AMF and HTTP endpoints on the server. The servlet API requires a request-handler thread for each long-polling or streaming connection. A thread is not available to service other requests while it is servicing a long-poll parked on the server, or while it is servicing a streaming HTTP response. Therefore, the servlet implementation does not scale well for a large number of long-polling or streaming connections.

The NIO AMF and NIO HTTP endpoints address this scalability limitation by providing identical transport functionality from the clients perspective, while avoiding the requirement of using one thread for each long-polling or streaming connection. NIO endpoints use the Java NIO API to service a large number of client connections in a non-blocking, asynchronous fashion using a worker thread pool.

Update: Here's more info from Adobe:

Tom Jordahl:
http://tjordahl.blogspot.com/2008/04/livecycle-data-services-26-public-beta.html

Damon Cooper:
http://www.dcooper.org/blog/client/index.cfm?mode=entry&entry=38AE015E-4E22-1671-53836F3A7F7AC22C
http://www.dcooper.org/blog/client/index.cfm?mode=entry&entry=38CBD3C4-4E22-1671-54399419A362F23B
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Andrew Trice
Principal Architect
Cynergy Systems
http://www.cynergysystems.com