When an idea "falls out of the sky" (for a new business, a product, a song, a story, or anything "original"), it hits about a hundred people simultaneously. No matter how unique and inspired you think your "big idea" may be, it's important to remember that 99 other people got the same idea at the same time.
84 of those people are too wrapped up in their daily lives to realize they've found the business equivalent of a treasure map, where "X" marks the spot. For them, this revelation will never amount to anything more than a subconscious flash.
The other sixteen people are well aware that inspiration has just bonked them on the head. Twelve of them will never follow up on it, however. Sure, they'll realize the treasure is out there, but they won't feel they are in a position to go after it. For a variety of reasons, they'll leave it for someone else to find (and when someone else does, all twelve people will say, "I thought of that!").
Four people will actively pursue the treasure, and seek to bring this new "big idea" into business reality. In other words, it's a four person race now, and whoever gets there first, "gets the gold." Here's the really important part. One of those people has 24 hours a day available to dedicate to the effort. One of them has a ton of money to spend. One of them is a freaking genius. The fourth one is you.
You see, the real threat to your success is not the people you'd initially ask for help. It's those other three guys who got the same idea at the same instant - and who have more time, money, and knowledge than you do to make it happen. They're going to beat you to the marketplace if you don't keep up. Someone in your network of contacts has the edge you need.
Knowing Your Network
Are you hesitant to share information with others? In a community like this one, the overwhelming majority of people are busy with their own big ideas and "treasure hunts." They're not interested in yours. Quite a few are only here to sell you something. They don't want your idea, they want your money.
The rest of us are willing to offer suggestions and advice as time permits. To do that, we have to see your "treasure map" (the details of your idea and plans). We can only offer guidance if we know where you are and where you're trying to go.
An "idea" has no tangible value. The value comes from advancing and refining the idea, not from the idea itself. (You can't "spend" the map, only the gold.) The law agrees. There's nothing an intellectual property attorney can do to protect an idea.
What you can do is buy a bound journal to document the development of your idea on a daily basis. Ask a disinterested third-party to periodically review, sign, and date your entries. You can also ask those with whom you share key details to sign a simple confidentiality agreement. Since it often takes years for a patent or trademark to be registered, this is very often the type of documentation that decides ownership anyway.
Finally, don't be a "one-hit wonder." The combined skills to conceive an idea and develop it into a profitable business are rare - but people who have that ability can do it over and over again. Lennon and McCartney didn't stop at "Love Me Do." Edison didn't invent the Electrical Vote Recorder and then retire. Like them, your best ideas are yet to come. Don't limit yourself by over-protecting the first one. Your goal is to prove to the world that you can find treasure. Once you do that, people won't steal from you - they'll line up for the privilege of financing your next expedition!