I was recently reading an article from the Harvard Business Review (www.hbrreprints.org) called "The Innovation Value Chain". I found it very interesting that when discussing problems with ideation most people think we need new ways to get ideas.
I always assumed that most of the time getting ideas or gathering them was the most difficult thing with ideation. In this article it discusses other problems that people have with innovation such as an effective way of evaluating all the ideas coming in. They call this process screening or idea conversion.
I typically ran into companies who had some form of screening process in place, but had a hard time getting new ideas. I was recently talking with a company that was struggling with screening and disseminating new ideas. They referenced this article and explained that they had many "Voice of The Customer" programs and were capturing many new ideas, in fact, it was more than they could handle.
In the product management space we find lots of vendors and analyst addressing Idea Capture or Gathering and very few that address the screening or conversion process and what the article refers to as the diffusion process (spreading ideas throughout an organization). I've worked quite a bit with people setting up stage gate processes and the screening section and have thought that you can't have too many ideas. While this is true if you have a good screening process, I've found recently that that isn't always the case.
In my experience (see my URL) the issue in innovation is never about the ideas, it's about the execution against those ideas. If anything, innovation teams need to know how to throw out or shelve ideas.
I agree with James, when dealing with mass amounts of ideas, you need a quick way of going through those ideas and identifying the ones that you will and will not consider in your innovation excerzises. I use risk vrs reward, with a quick risk estimate for change in operations and change in user experience of high, medium, and low. Then I will do a quick estimate of reward, maybe totaling up the number of customers/internal members that suggest that idea, or a quick estimate of expected revenue, or alignment to strategy.
But without some sort of quick screen people tend to hold on to thousands and thousands of ideas that will never be considered.