[ZanderEarth32]

Why exactly would Kickstarter make unsuccessful projects easily found? Nothing can be done with a project that has been unsuccessful, so Kickstarter is actually providing a better experience to it's users who are looking to fund projects that still can be successful.

The reason eBay might keep already sold, or not sold items indexable is because they just might not care if users find those items. eBay also deals with 'commerce' on a completely different scale than Kickstarter. They sell millions of items, daily I would think. One unsold copy of a book doesn't tarnish the service. As for Amazon, if an item is sold out it doesn't mean the item won't become available at a later point. The shopper can probably add the item to a wish list, find a used version or be notified when the item is available again. You can still perform an action on the item, unlike Kickstarter where there is nothing that can be done with the unsuccessful project.