Given the number of people trying to beat the market with their personal algos, at least a few are certain to beat the market for many years, even if their strategies were no better than random.

Edit: I don't mean to suggest that it can't be done. I'm just suggesting that the existence of people beating the market may not be a good indicator of your ability to beat the market.

Aneth. . . . you're reading our mind. Come back to Quantopian on Thursday. I think you'll like what you see.

Yes, there are people who trade today and make money using algorithms. They are few and far between, mostly because the toolset is so hard to build. Data, backtester, trading platform, etc. all take a long time to build. We're trying to make it much easier by providing all the tools. You need an idea; we'll make the rest work for you.

Not that I know of. Typically after they start beating the market for a while and get a few $M in the bank, they hire other people and build infrastructure. Then the algorithm ceases to be "home grown".