It is no secret that both Google and Bing want you to report search spam to them and people do it. It helps them both manually and algorithmically tailor their search ranking algorithms to be better quality.
Google has gone to lengths to encourage users to report spam by creating chrome extensions, forms in webmaster tools, generic forms and heck even the block sites feature. But Google has never promised action on those spam reports nor have they offered any monetary reward for these reports.
A Bing Forum thread has one SEO recommending to Bing to offer an incentive or "small reward" for users who report search spam to Bing. If the spam report leads to a nice unearthing of a spam technique, give the spam reporter something nice to encourage that spam reporter and others to report spam more often.
Side note: The interesting thing about this post was that the one who suggested it dropped a anchor text rich link to his business.
Bing's response was non-committal but yet not shut down completely. Wil from Bing said:
Thank you for your feedback. While we cannot guarantee all requests to be granted, we will certainly have our team review this and consider it in future releases.
Do you think Google and Bing should offer incentives to report spam? Take our poll:
Forum discussion at Bing Forum.