What are the trends in those things that make groups of humans smarter? e.g. How will world capacity for information communication change over the coming decades? (Hilbert and Lopez's work is probably relevant)

A social / economic / political system is not just analogous to, but is, an artificial intelligence. Its purpose is to sense the environment and use that information to choose actions that further its goals. The best way to make groups of humans smarter would be to consciously apply what we've learned from artificial intelligence to human organizations.

For example, neural networks have rules that adjust weights between nodes to make the "opinions" of certain nodes more important in particular situations. A backpropagation network with one hidden layer basically discovers which (reduced) dimension of input patterns each hidden node layer is an "expert" on, and adjusts the weights so each node's opinion counts for more on the problems with components that it is an expert in. We could apply this to our political systems today, replacing the Constitution with a better algorithm for combining votes and using predictions or standardized tests to adjust the weights given to the votes of different people on different issues so as to maximize the information-processing power of the body politic.

Of course, this would be politically... difficult.

But we might see something like this happen within corporations (my money's on Google), or in small progressive dictatorships like Singapore.