You do put money into a company when you buy its shares ... during an IPO. Meanwhile, owning shares of a company convey fractional ownership of it, its assets, and its future earnings. People will consider the stock price of a company relative to its assets and earnings (P/E) as an indicator of whether the company is overpriced or under-priced.
No one really notes the "total volume" of the trades of stocks, which is what you're asking for for Bitcoin; it isn't really a meaningful number. If people pass a stock
- or a Bitcoin - back and forth for 10 trades for [$99, $101] or for 100 trades for [$99, $101], it isn't really meaningful.
The best you can do for Bitcoin is to try to gauge the "depth of the market" right now, ie, how many "buy" and "sell" orders are out at what prices, how much Bitcoin you could buy or sell right now and what the average price you could buy or sell a large quantity of Bitcoin at. (Eg, if you wanted to sell X Bitcoin, you might be able to sell X/2 Bitcoin at $PRICE and X/2 Bitcoin at $PRICE/2, for an average price of $PRICE*3/4.)
