Ben Rockwood has a brilliant discussion about the supposed OpenSource bubble, which is itself a response to this piece by Martin LaMonica.

Many of us have been through bubbles before, the dot.com bubble being the most recent (and possibly the most extreme) example. Read both before you make up your mind, but I'm beginning to wonder if there will be some kind of fall out. I think this is especially true if consider the comments made by Jason Matusow, best covered and described by Jason himself here.

I don't agree absolutely with Jason's comments, but I think he makes some valid points, as do Ben and Martin.