Also to consider: The system regulates the number of BC mined to 6*50 per hour in the moment. This means: The more miners there are, the less each of them gets. The size of each share is proportional to the hash-rate of a miner, so you may out-power other miners for some time, but in the end, your share is always proportional to the total has-rate of the all miners. So if you think to tell all your friends and their cat: Think again. OTOH: The more people know about BC, the higher the exchange rate may get...

And all this has nothing to do with the current exchange rate of BC. This rate mainly depends on market expectations and influx of real money. So expectations that the price of BC in $ will grow together with difficulty may be disappointed. In the moment I think this is simply coincidence because both influx of new miners and influx of money stem from public interest and this grow in a similar way.