Anyone see a problem with that approach?
What you're proposing is a little like building a house to see if a customer likes enough to buy it, without letting them pick a layout/blueprint they like, or the conversation that goes into the blueprint of ensuring the customer would want the house.
First, find a target customer. Learn what their painpoints are. See if they're willing to pay for that painpoint. Then, build something to sell to them. This allows you to explore multiple hypotheses, instead of going to them with your idea that ends in a yes or no. By involving customers from the get go, they are more engaged, invested and committed, especially if it could make their life easier.
You will find that this path will reveal to you a completely different set of priorities and pain points that would be small to do, but have a huge impact, which is a great basis for an MVP.
By doing it doing it in reverse, you're hoping you take a stab at it and it pans out, at the expense of not doing the idea development upfront before writing a single line of code. The best way to "market" is to do it as you explore what to do and build a mailing list. Share your journey through a blog focussing on the life and business problem you're solving (not your code or tech breakthroughs).
Learn about your customer instead of guessing your way through what someone might want. Having domain knowledge in a field that you build something for could be helpful but you still have to validate, first, if anyone will pay for it. That's the scary, and what makes it a real business (self sustainable and makes money for you).
Of course if it's just you and you're committed to launching your product regardless of whether you get investment or not, then you might as well code it up and see what happens!
A preferable approach is if you can test the business/app soundness before investing 5 to 6 months in programming effort. If you can test two or three app ideas in that same period you significantly increase your chances to hit gold.
That mentioned 4-5 months will, statistically, be for nought if you don't do the important marketing/prep work ahead of time.
You are wasting your time by building the product first. You have to do the inverse. Become a marketing money for the first four to five months and do minimal coding (that is why its called an MVP). Once you have people buying your product, then you focus on improving it (or refactoring to rails, for example). If you do get funding, then use the money to grow the business and software at the same time/ratio.
Reason why this may seem a bit alien to you is because it requires you to go into marketing mode from day #1. Something you may not be comfortable doing.
Plus, marketing a product is just not about adwords, blog posts, and link on hacker news. It requires you to actually talk to other people directly. This is where a lot of introvert hackers ( like me ) quit.
The purpose of the MVP is to get something good enough out of the door so you can focus on testing. Testing sales, marketing, user experience, etc. Once the initial testing is done, and the product has proven itself to be profitable if not then iterate/pivot), then you go and refactor the software if, and only if, the costs of doing so are worthwile.
I know of products out there that are complete and total bowls of spaghetti that make a lot of money and would be re-written by most of us. But they are profitable, and that is the ultimate test for a product. Does it sell?
Now Zynga, well, they are a bunch of good intentioned developers being led by people with a focus on short term money and not long term value.
You have a big assumption: Product X will be valuable enough that people in group Y will pay for it. Your way of testing that assumption is to spend 5 months coding plus N months trying to sell it.
So at the end of 6-12 months, suppose you discover that Product X is in fact not valuable. All of the coding time and a substantial portion of the marketing time will be wasted.
Ask yourself: what's the cheapest possible way to test your core assumption?
Anyway best of luck!
In my case my product is really different and I dont know how I can get people to understand what it is without actually getting them to play with it.My belief is that my MVP will be the best tool for building hype.
EDIT: check this http://www.quora.com/Dropbox/Is-the-original-Dropbox-private...