If you have a great idea, share it. It will improve the idea. I think this is really a good idea. That is why I have an idealog (not exactly startup ideas but product/tools ideas). And plan to move more of my ideas from my personal ideas to the idealog.
Go ahead and Tweet it (see whether you can say it in 120 characters). See whether it gets re-tweeted or whether some one sends you a DM. If you want to expand on it, you may even want to blog it. Here are some benefits you find in sharing your ideas:
1. The chances are that among your readers, there are more customers and partners than competitors
2. Not many people would have thought through how to implement it as you have done. So you have a headstart
3. Some one may tell you that this idea is already implemented which may help you in several ways.
4. Some one may suggest other ideas (more useful ones) that they may be actually willing to pay for.
5. Some of our best products were ideas we shared at a very early stage and refined based on feedback to become successful products