Is there a platform on the net where people can share their business ideas (at a concept level - not just the crude idea but also their visions about capital raising, business model, consumer response, management, etc) and give each other feedback?
We have platforms and forums for web designers to peer showcase their work and receive valuable feedback, we've got the same for visual artists but I find it hard to stumble upon such for aspiring entrepreneurs.
(By the way, such a platform could be useful for mature entrepreneurs as well, when starting a new product line/ a new branch of their business, etc.)
There are online communities and even groups on LinkedIn for some of this. I would just be careful 'sharing' and that it is not an 'idea' anyone else can implement easily. There is also Product Incubators (if it is a product), but perhaps someone with more experience can speak to these. Even some of the Universities around the Country are doing this also. Just be sure to protect your 'idea'.