ICO contract: the missing piece of the puzzle, what happens after deployment?

Question

I have gone through pretty much every solidity example available on the web, and deployed lots of examples to a test network Using Mist wallet.

Let us assume we have created the perfect Etherium ICO smart contract, and deploy it to live, paying the necessary ether.

The question is what happens next - how do investors purchase the ICO tokens?

Does this happen through:

1. A token exchange like kraken or bittrex? I.e. the ICO contract is just another (ERC20) virtual currency.
   1.1 If this is the case, can investors only purchase with Ether? Would the exchange manage the fiat currency and other currency conversions, so the investor thinks he is purchasing the tokens say with bitcoin or fiat, but actually the bitcoin or fiat is being converted into ether behind the scenes?
2. your own custom website acting as the front end of a DApp using your token as the backend. This is great except to integrate a payment provider requires a longer standing company with a bank account, something many startups and ICOs dont have yet.
3. A specific ICO portal (like tokenMarket?). Presumably to work with such a portal, do they have a standard for ICO contract interfaces similar to ERC20?
4. Nothing - the investor has to know how to manually transfer ether to the ICO smart contract address. This sounds risky for the investor, but I have seen this on some ICO sites, like lordmancer2.

Secondly, what determines the price of the ICO tokens? Is it fixed (with discounts for volumes), or completely market led (like a real IPO has an initial price, then it could go up or down depending on the market). Is the initial price set in Eth or fiat? Presumably Eth, so would have to be set on day of putting the contract live?

Obviously this post does not include the non-tech side of ICO including white paper, reputation, marketing, community management etc.

Answer 1

The purpose of your ICO / Crowdsale smart contract is exactly to define all the variables you are asking.

You are the one that determines the price during the ICO, which can be as simple as a flat-rate or use complex formulas to define rates based on volume or purchase time.

You are also the one that would define how to accept contributions/purchases. The smart contract only accepts eth as payment, of course, so if you wanted to accept fiat or btc or some other currency you would have to develop such mechanisms yourself, which typically revolve around having a manual function to give tokens to a user, assuming you processed their payment off-chain.

Once the ICO is finished, the tokens would be available for trading, which requires that you strike deals with different exchanges to accept your token for trading. From that point onwards, the market itself determines the price. People would have tokens which they will want to trade on these platforms and you have no saying on the price (well, you actually do by doing what you said you would do to make your platform growth, generate more need for your token and have people buy more of it, increasing its price).