Not every idea is a good idea, and this is certainly true for start-ups. There are some business models that can be replicated over and over again to success, but some ideas just aren't that easy. You're more likely to get struck by lighting than to make the next Facebook `killer'.
This isn't to discourage you from trying. Far from it. Try, succeed, fail, win, lose and keep on trying. But it's unlikely you'll beat the big players (or someone successful) just by attempting what they are doing (you might, it's just that it's unlikely).
This question was asked recently on Quora: “What are some startup ideas that frequently fail?” … even after various forms and variations, what ideas still fail a lot? There are some really great answers, and here are a few of my favorites.
- Craigslist killers – but not sites that attack individual categories on Craigslist (see diagram in this question's summary)
- Business that let consumers scan some kind of code, number or barcode in real life, with some special device, or lately their phone, and they get sent a URL, ad or coupon in return.*
- Website micropayment donation. (and variations there of)
- Anything that makes programming “easy for non-programmers or businesspeople” (On a side note, this is just a bad idea in general anyway.)
- “eHarmony for jobs,” has consistently failed. Huge market, huge problem, many attempts, mostly failures.
- Consumer recommendation services(This is something such as showing you suggestions of what to buy based on your friends list and what not.)
- Killing the Business Card.
Again, this isn't to discourage you from trying things. It's just these are ideas that commonly fail over and over again. As one user put it (and put it very well):
Nothing fails persistently. Everything that works is a re-invention of some existing idea that has failed before – done right.
Search engines “failed” as a business before Google came along. Online transactions failed before PayPal came along. Email “failed” before Hotmail made it accessible online. etc etc
So run with it and see where it takes you. At least you'll learn something out of it all!