What is Bitcoin?

I recently emailed someone who has a website that keeps a running record of returns (i.e., equities, bonds, gold, etc) with nearly 100 years worth of data and asked if he could start tracking Bitcoin from 2009. The person responded, "As what? A currency? A collectible? Bitcoin’s only claim to fame so far is that people trade it. Until its advocates figure what it is, I am not going to jump the gun."

Although I already know what my response will be, what do you guys think?

I already understand no matter what I reply with he won't include BTCs data because clearly he is uncomfortable with it and depending upon the person or organization, BTC has already been defined as one thing or another. Interestingly, gold can be a currency and a commodity.