This has been around for at least a few years. It's cool, but I'll warn you that some of the data isn't super-clean. IIRC, there were a few daily data holes, and even more so in the intraday data
However, for the price, it's pretty awesome to play around with.
"Can I redistribute the market data?
Unfortunately, at this time, opentick does not allow redistribution of the data due to various rules and regulations. However, when this possible, we would be happy to notify you." (from the FAQ)
but still, this is awesome... becoming a quant millionaire just got a whole lot easier ;)
I checked the site... Do they only provide an API or can we actually download the data? It looks like they charge money for NASDAQ and NYSE. It does seem like a stretch to call it open if they charge money and only provide an API.
Historical data should be available for free. The money you pay for real-time data is the exchange fee- ie it is paid to the NASDAQ, NYSE, or whoever. The exchanges do not allow real-time data to be offered for free.
Firms that compiled the data should sell it at whatever price the market is willing to pay. Just because the value of information tends toward zero, does not mean that the price should.
I didn't know there were wannabe quants on YC. I thought they were all on nuclearphynance. ( Which you should check out if you are interested in seeing how the real quants do things. Opentick was on np about 2 years ago. )
Wow! Companies like Reuters charge $5000+ per month per seat for data like this! Not to mention that their data is pretty crappy. Too bad they don't have any FX data.
Unless I'm missing something, they currently aren't letting people create new accounts. So whatever free data they have (and they charge for most things, apparently) is unavailable for now anyway.
However, for the price, it's pretty awesome to play around with.