In my line of work, I’m often asked to sign confidentiality agreements before someone will tell me about their business or invention. Most often, I refuse. Not because I’m interested in stealing their idea (ideas are easy, execution is hard) but because it’s very possible for someone to share information with me about their project, including it’s benefits, features and advantages without disclosing any confidential information or trade secrets.
Ron Docie, on InventorSpot, has a well written essay up about just this subject called Confidentiality Agreements For Inventors Without A Patent.
As long as you’re careful about what you disclose, it’s possible to make a preliminary presentation to a company to decide whether they are a match for your invention, or to receive a critique to see to what degree the attributes of your invention are desired in the marketplace without ever needing a Confidential Disclosure Agreement or “CDA”.