Startup Idea : Service to validate B2B ideas

We as entrepreneurs are trying to identify problems, figure out a solution and validate if we can sell it. What options do we have when it comes to B2B idea validation? Cold calling, emailing, ad words, facebook, reddit. I think there should be more advanced way.What if there would be a website which would allow you to create a short pitch and select from what businesses you want to get feedback. All communication goes through this website and from business perspective this website would be like public R