There was some work done by Sun recently on this, around last year I think, where they showed how much more performance could be gotten out of a system when flash is added to the mix. I can't quite find the link to the article now though. I'm sure there are others doing this too, but sometimes adoption rates are slow when there's not enough hype. But the issue is probably more to do with software.<p>I've been researching into this to try it myself for a database-centric web app, but I realized I'd have to write much of the software to incorporate flash. For example, you have to make sure that in-memory caches are delegated to flash and kept there according to an LRU algorithm. I'd also expect items stored in flash to be promoted to in-memory storage when accessed often enough, and demoted to disk when used less. And I'm sure there are other intricacies I haven't thought about that need to be considered to make a three-tier storage system work well.<p>Rather than writing application-specific code for all this, there really should be some general solution that handles this automatically.