Whether you’re talking about Facebook, Google or Apple, there’s no doubt that Silicon Valley is capable of producing some big winners. It’s also capable of producing plenty of companies you’ll never hear about, which fizzle out without ever making much of an impact — or a return for their investors.

There’s also a third category: the companies that appear to be set for superstardom, only to plummet back down to earth. Reasons can vary from bad management to failing to deliver on promises to, sadly, just being way ahead of their time. Here are eight failed tech companies that rose to power and fell from grace — in a big way.