[Another reply I attempted to post somewhere else only to find out after hitting submit that I needed to sign up for an account... fucking bullshit: http://news.ycombinator.com/item?id=628875 ]
Haven't we learned from the dot com boom that ideas alone have no value? Scientists formulate hypothesis after hypothesis and test them. An idea is at best an untested hypothesis and at worst a thought that seems novel to the uninitiated but is well understood by even an acolyte. You're muddling your own idea down by talking about "ideas". [Ed: this person suggested an "idea search engine"]. Talk about concepts. Do a Markov Chains style graph between words, linking transitions and transition frequencies between sentence fragments (words, compound words, phrases, whatever). Then you have a chatterbot for people to talk to. Google uses Patricia Trees for something similar but that operates at the character level. Joking aside, that combined with Single Value Decomposition could be used to find other people writing about similar ideas. No reason you couldn't automatically scrape Twitter or other blogs for fodder for this database. Stepping back here, there are no original ideas here: these are known algorithms combined in obvious ways. That doesn't mean that the end result has no value. We programmers need to pay homage to the discipline of engineering -- knowledge skillfully applied -- rather than holding aloft the pseudoscience of men in suits sitting in board rooms having "ideas". But that doesn't mean that as technical folks we can't be exposed to more algorithms and applications for those algorithms.
What's the difference between an idea search engine, knowledge base, or concept base? Offhand, my first guess would be the correctness of the content with an "idea database" having little or no more higher quality content than a "concept database".