but anything innovative, new and unseen - never post *that* on internet, that would be very naïve and even stupid
I disagree -- I can't really explain why any better than Daniel Cook did so in his blog entry "why you should share your game designs".
I often hear from would-be developers that they're concerned about their ideas being stolen, but I never see any actual examples of it really happening in practice. An idea is just a starting point, and even if it actually catches someone's attention to the point that they want to work on it rather than pursuing their own ideas, it's pretty unlikely that they'll produce exactly the same (or even a particularly similar) game.
It's also worth noting that feedback from friends and family isn't always honest -- even if they try their best to make it so -- because they have an emotional attachment to you. It's also likely that you have surrounded yourself mostly with like-minded people, and feedback from the differently-minded can be invaluable.
Obviously different people are comfortable with different levels of sharing and you should stick with whatever you find comfortable, but many people find feedback to be invaluable, the stealing of ideas seems to be very rare, and I think everyone can agree that whatever your comfort level you need to stop short of "stupid paranoia" (link from Tom Sloper's list of "stupid wanna-be tricks").