Then it doesn't matter, does it? As long as my algos keep working I don't really give a crap if some programmer at Quantopian or anywhere else is investing his $20k in it as well. The scale needed to arb away the profitability of most of my algos would be at a big hedge fund level and I don't flatter myself that my algos are with the effort and risk for a big hedge fund to steal.
Relax. I have no dog in this fight. I was only pointing out that you may never know if your algo is stolen. I tried to make that clear by starting the post with, "I'm posting only to say..."
Out of curiosity, why do you hate Python? I have never been able to get into Python and I think it is because I cannot stand that indentation is part of the language (and the problems that arise because of this - like using tabs vs spaces but you can't use both). That being said, I do like Quantopian and have tried writing a few algos with it.
I have 2 main objections to Python: Indentation rules - Every mainstream language since Fortran-IV and COBOL uses braces for if, for, while etc statements. They stopped using indentation for a reason: it's too error prone. No types - I remember when "strong typing" was first being mentioned and was a big deal and considered a good thing. Now with Python you don't need to declare variables (or initialize them for that matter) which is crazy. Strong typing and variable initialization are hallmarks of disciplined programming. Anything that encourages design-by-hacking is bad, period.
Steve Cohen = big hedge fund. Just invested $250M in Quantopian algos. They say they will use the best algos from the database and promise a cut to developers, Remember that most get only once or twice in lifetime to discover true edge. Why would you want to risk that? You can develop the same edge in any standalone platform and trade it yourself. Quantopian may be great but still if you can do the same thing with 100% security why going for python, indentation and all the other little problem associated with using that language as others described?
Why using any vendor to develop or sell a system if it works? Just trade it yourself with money from relatives and make everyone rich. The rest are excuses for snake oil.
So, every system, mutual fund, hedge fund, etc. is snake oil because they have clients? Because YOU wouldn't take on clients if you knew how to trade...except your Mom and Dad.?
I don't know how to make this clearer, if you think developing winning algo's are a once or twice in a lifetime accomplishment and/or someone is going to steal your algo and harm you, neither Quantopian or any other commercial backtester is for you! Learn how to program and spend a few thousand hours writing your own backtester instead of developing algos. There are some people for whom free well-written commercial backtesters are a spectacular resource and some people who choose not to use them because of IP concerns. If you're the latter then just don't use them, simple enough. It's actually in your best interest to let the rest of us rubes spill our secrets everywhere while you coddle your goose laying the golden eggs, so I'm not sure why you're trying to convert us.