I didn't know that coinmarketcap had historical page data, thanks for the link! Would be nice to get better than weekly precision, but it's better than nothing.
https://bitcointalk.org/index.php?topic=199685.0Since the requirements for a coin to be added to the site include being tradeable on a public exchange with an available API, it stands to reason that they have a bot collecting the stats from the exchanges via their respective APIs. Essentially, the information on that site is just compiled publicly available information from the various exchanges hosting and trading those coins.
Hmm, seems like that is probably the case. I guess if there was a paid service that had the full data, it would be more readily known?