Hey, I'm super new here too though I too made the mistake back in 2009 of thinking Bitcoin was a "fad" that would pass. I was actually "donating" the CPU power of 3 computers at the time to a prime number network...if only I had been mining instead
I think the biggest issue with 28nm vs 15nm is that of startup costs
15nm is still a very new development, and as such, only companies with the appropriate R&D budgets currently have access to it.
I'm certain that it will make it's way into the Bitcoin world soon, however, as I understand it, just as important as the mining speed would also be the mining efficiency.
This new chip process will be much more helpful in offering more computational power per KWh than it will be in producing raw GH or TH/s
Thus while network capacity (and unfortunately difficulty) will jump again, I think the bigger story will be the decreased effect on energy prices in determining margins.
This is the main reason I'm focusing mainly on Altcoins that are scrypt based... still a chance there to GPU mine whereas I totally missed out on that with Bitcoin
-Derek
