Bitcoin Forum

For the first time ever, the market capitalization of all bitcoins currently in existence is over 300 million. (NB: right now, it actually isn't, but it was for a brief period of time yesterday.)

The market capitalization is an upper bound on the total size of an economy. For many reasons, the total Bitcoin economy is actually smaller than this; a few include: some bitcoins are lost or destroyed, some bitcoins are dormant and currently unable to be spent, and if all bitcoins were spent immediately the price would drop quite a bit. However, it is an interesting statistic to use when calculating Bitcoin's size. Now, Bitcoin is likely the largest incompletely-backed virtual currency in the world when measured by market capitalization.

From here, what next?

Correction the BTC money supply valued in USD exceeded $300 million.

Also isn't Bitcoin larger than Linden Dollars?

Can't seem to find a stat later than this one but...
http://community.secondlife.com/t5/image/serverpage/image-id/21003i34955CBE79B3DFF9/image-size/large?v=mpbl-1&px=-1

Would indicate the Linden Dollar money supply is valued on the order of ~$30 million USD.

To put in perspective Playboy has a market cap of 258mill and Buffalo Wild Wings 358.

That's an impressive number, as was reaching 0.25 billion, but considering a good fraction of those are effectively lost/unusable, I'm not sure that's a sign of anything.

Fixed. That's what I get for using Quora as a source.