Thanks. I looked at CrowdFlower. I don't see that it is doing what I had in mind.
I was thinking of something where the average guy could:
1. Download the Captchacoin client just like you download Bitcoin-core;
2. Install it on your computer in just the same way;
3. "Mine" captchacoins by solving captchas which the client would create and place on your screen.
The client would provide complex (but doable by anyone) captchas right on your screen, and when you solved them you would get a coin. The more you solved, the more coins you would get. They would be stored in your wallet, and when you went back online, they would be uploaded to the Captchacoin blockchain as yours, in one of your wallets. If your OS or computer were in need of an upgrade, and the system crashed, your latest captchacoins might be lost.
The more coins that were mined, the less the value of each, not because of any client-built-in devaluation, but because the more of anything that there is, the less rare it is, and the less value it has. People would have to keep mining to keep value. In general, hodling would be of no value. This means that people would have to trade their coins for cash, gold or products if they wanted to maintain value. This means that there would be a growing market created.
If devs wanted some value to remain, the whole client could be built in such a way that later coins only held partial value of earlier coins, based on some simple "halving" algorithm... something like mining bitcoin blocks changes every 4 years. The halving wouldn't be based on time, but based directly on the blockchain record number of coins. There would be no limit as to the number of coins that could be mined/solved.
Does CrowdFlower provide the ability to do something like that?
Crowdflower will deliver capchas to your desktop, you solve them, then they give you bitcoin. The employer who hires crowdflower to subcontract to you is a spammer of course.
More practical as a currency would be have an algorithm that allows any human input, then have people respond to that input, or reate bots to respond to it if they can.
For example
1) You receive questions on the blockchain and are paid a coin to answer them, or to create a bot that can answer them.
2) Somebody else who wants your work, or who wants to subcontract bot technology, provides their latest algorithm for generating questions.
You would have a coin that could be used to subcontract any kind of development quickly and results based with no bureaucracy.
add
If your goal is specifically spam then you could make a coin like that but hopefully nobody would support it.
If Crowdflower goes down, are they open source so that anyone could maintain their development, and the coin keep going?