> Love to tell my horror story re: my experience dealing with a Fortune 50 company.

A couple of points:

1. Obviously this is very different from pitching to an angel investor or venture capitalist, who might be unlikely to care about your secret technology. As you discovered, it's entirely possible that BigCo's engineers were very interested in learning what you were doing so they could do likewise, ideally without having to pay you anything.

2. Courts will sometimes enforce trade-secret rights even without a written NDA, if the circumstances were such that the party receiving the information implicitly agreed to keep the information in confidence. But that can be a really tricky proposition to prove, and will vary with the jurisdiction.

3. A written NDA might or might not be of much value in a situation like this.

A) BigCo might not want to sign an NDA. That's a red flag right there, of course. BigCo might even want you to sign an agreement saying that anything you say to them is not confidential (this is not uncommon, because big companies get a lot of idea submitted "over the transom" and don't want to have to deal with lawsuits from cranks who re-invented the wheel).

B) NDAs usually have carve-outs that say that "Confidential Information" doesn't include information that was published or otherwise known to others before disclosure (or that becomes such afterwards). BUT: Under U.S. law, a specific selection or combination of individual pieces of public information can be protectable, just as Kentucky Fried Chicken's secret blend of 11 herbs and spices is (reportedly) protected as a trade secret.

C) You want to be careful to comply with any requirement in the NDA that confidential information must be disclosed or summarized in a writing that's marked "Confidential" or "Subject to Nondisclosure Agreement" or something like that, on pain of losing protection. For example, in the Convolve v. Compaq case, the computer manufacturer Compaq (now part of Hewlett-Packard) defeated a claim of misappropriation of trade secrets concerning hard-disk technology because the owner of the putative trade-secret information didn't follow up its oral disclosures with written summaries as required by the parties' non-disclosure agreement. [1]

D) Enforcing an NDA can take a lot of time and money, especially if BigCo is convinced they haven't done anything wrong. On the other hand, sometimes it can pay off, because a jury might well punish a company that it found violated an NDA. See, e.g., the 1996 case of Celeritas Technologies v. Rockwell International, where a federal-court jury in Los Angeles awarded a startup more than $57 million, and the judge then added $900,000 in attorneys' fees, because the jury found that Rockwell had breached an NDA. [2]

4. Suggestion: Even for non-secret information, an NDA might be negotiated to include the equivalent of a break-up fee. That is, even if it turns out that the secret technology wasn't a secret after all, but the receiving party didn't know the technology, then the receiving party might be required to pay the disclosing party something as payment for "show-how" (as distinct from know-how), in return for having taught the receiving party about the information, thereby saving the receiving party from the time and expense of having to find out the information on its own.

[1] http://www.cafc.uscourts.gov/images/stories/opinions-orders/...

[2] http://scholar.google.com/scholar_case?case=1681061439024444.... Disclosure: I was part of Rockwell's trial team in that case.