Communications' Exponential Growth Rates

Everyone in high tech is familiar with Moore's Law and most are aware that similar exponential growth occurs in many other measures of digital technology, for example disk storage.  What about communications?

Gordon Moore referred to the number of transistors that could be inexpensively placed on an integrated circuit.  The Wikipedia entry for Moore's Law mentions other measures that are increasing at exponential rates as alternate "formulations" of Moore's Law, e.g., computing power, hard disk capacity and pixels per dollar.  Unfortunately, Wikipedia (at least so far) doesn't have accurate doubling rates or supporting data for these other measures and they present little on the area that most interests me -— communications.

Why care?  Different rates of exponential growth can cause substantial shifts in the technology landscape, some of which I'll discuss in subsequent posts.

Here are the doubling rates for some measures I'm interested in:

Note 1:  Density at minimum cost per transistor, see the Wikipedia article on Moore's Law.

Note 2:  12-24 months depending on how computation is being measured.  See, for example, the arguments here.

Note 3:  Since the mid-1990s, disk capacity has doubled  every 12 months.  In earlier decades, it was more like 15 months (based on calculations from this data), but since 1995 (through today) the 12 month rule has held.

Note 4:  Based on these data points:

Note 5:  The classic reference is Odlyzko & Coffman (2001) (also 1998).

Note 6:  My personal Internet connectivity is documented here (for data to me).  For data rates from me to the Internet, the Feb 2007 value is 2.7 Mbps, which implies a 26 month doubling period (versus 20 months for data rates to me).