The only honest counter-point to "ideas are a dime-a-dozen" is that the 19 years experience I have of unique experiences online, and in web development - throughout having spent that time focusing on different-but-connected problems for long periods of time - will result in me ideas that are nuanced and unique to me and my understanding. Most of the time people won't be able to understand the value of what your presented idea - they have less of your experiences that lead you to this same point.

This is in fact the problem with finding investment money, especially if you're trying to disrupt a market and haven't proven your nuanced theory yet - which is why it's best to find investors who invest in similar ideas or that you could fit under their investment thesis umbrella. Or where you reach traction of whatever sort, so investors can see evidence of something working - so then they can be put at some ease.

Knowing something - figuring it out - before someone else does is a competitive advantage, and a needed one if you want to own or be first to disrupt a market. Execution is also very important - though if you're a creative person, who can come up with unique theory and see things others perhaps can't - then are you as good at execution? Perhaps there are others that can execute quicker and better than you.

Or if you're Mark Zuckerberg - you could be a developer hired to help develop ConnectU - and then lead the brothers on, pretending it's almost ready - meanwhile working on your copy, The Facebook - and launch before them, because you yourself even stated to a friend in an online message that "there's not really room for two" platforms like ConnectU/Facebook.

Can another Twitter exist - in the same market space? I don't think so, not with a ton of capital invested and so long as Twitter doesn't do something stupid - which I don't see happening based on everything they're doing. P.S. I would buy Twitter stock if I had money to. Facebook on the other hand continues to do things people don't want, violates and abuses people's privacy and settings, on a fairly regular basis. Facebook is ripe for disruption, even if merely for treating users better.

These nuances you discover are reasons why you don't necessarily need to worry about others executing your ideas well, though some people are very good at reverse-engineering, and all they need are some keys - and they can start to unlock the rest. Some people have access to a lot of resources to copy ideas too - a well-known firm in Germany (?) who copies most anything successful: Pinterest / Pinspire, Stripe / etc..

The real solution is be smart about what you tell people, who you tell what to, and when you share certain parts of your idea - otherwise you're being naive or just don't care about the overall success of your business. It's engineers, developers, who these days are mostly getting funded and becoming successful because they can build product - get it to a point where it's ready to start scaling and get resources attached to them to turn them into a real business as quickly as possible. If you're just an idea person, without personal wealth or family wealth, and no technical skills - your chances of success are very low in many business arenas.

It all really comes down to how serious you are and how big and stable of a business you want. There are tons of small ideas that aren't done because you won't make a lot of money doing them - they aren't defensible in that way either - so if you enjoy doing it or want the experience to learn some things - then that's great - though not likely something you can retire on. There are the outliers, a more in line use of the word, who make something small that becomes big and then they can sell it off - though the internet is no longer in its infancy, and it is a serious competitive business environment.

My two cents.