I have found that external innovation success usually occurs when a technology seeker proactively pursues external solutions for time sensitive business needs. In these instances, a qualified solution has an internal business customer. They either find viable solutions themselves or with the assistance of a technology intermediary. Appropriate solutions virtually never arrive via an unsolicited submission.

Yet many companies solicit external submissions, invest considerable effort to their review...and then reject virtually all of them. This can't possibly be an effective use of resources. It also leaves everyone feeling like they've wasted their time. If companies want to be truly open with prospective external partners (and make their efforts more productive), they should do these things:Inform submitters up-front that success is unlikely, as very few submissions are able to meet the company's rigorous standards. Communicate explicitly that if the submitter wants to try anyway, their submissions must nominally have certain technical and performance credentials. Otherwise, don't bother making the submission. 

Reject mismatches and unqualified submissions within 1-2 weeks. It shouldn't take 4-8 weeks to recognize a poor fit. 

Mandate effective evaluation procedures and behavior standards. A corporate gatekeeper recently apologized to me for his technical colleague's unprofessional behavior, explaining "that's why we don't let some of our scientists deal with outside people". Does anyone evaluate the evaluators? 

Companies committed to "actively shop submissions with an intent to buy" instead of engaging in ongoing and non-committal "browsing will make much more productive use of everyone's time.