IN THE SUMMER OF 2004, two red-hot Silicon Valley start-ups were preparing initial public offerings. One was Google. The other was Nanosys, then the flagship of the emerging stream of companies focused on nanotechnology -- the science of the very small.I gave thumbs-down to the proposed $115 million Nanosys IPO in a July 5, 2004, feature called "Sweating the Small Stuff." I noted that Nanosys was little more than a collection of early-stage research projects. It had a pile of patents and a stable of Ph.Ds, but scant revenue, no products and no idea when it might generate either. The proposed IPO was a cynical attempt to tap into what was then a certain level of mania about nanotechnology. But investors figured it out: The IPO was pulled.