[tx]

1.9 will introduce native threads, which aren't much better.

What? They're not only "better", they're actually _threads_, i.e. are able to run in parallel, you know? What are Ruby 1.8 threads good for, except for sitting on sockets?

[tesseract]

Producer/consumer where there are multiple I/O bound producers (examples that come to mind: RSS reader, web spider, multiple-file search). They can also be a useful abstraction for things like waiting for events from multiple sources, or running quasi-realtime simulations.

I agree, though, that real threads would be a significant improvement. Or better yet, MxN threads like GHC.