1) Would you use this website? If not, what do you use instead to perform market predictions?
2) Are there any other indicators you would be interested in seeing calculated?
Not as it is now.
I try to use whatever indicator sources I can find, with special interest in media and online discussion attention. Also, trade activity and usage using Bitcoin.
An example would be Google trends. If someone were to make statistics of Bitcoin trading activity from the merchants, not just the block chain, that might be interesting. E.g. somehow get rough sales volumes for Spendbitcoins, Casascius, ...? I don't know whether you can get people to pay for it, but it might get more attention than chart post-processing alone.