There is some evidence (courtesy of the IMF) that the economy in Sub-Saharan Africa is growing faster than the world as a whole.  Not by much but when you consider the considerable effort some of its governments put into preventing any growth, this has to be seen as good news.  It still lags behind the Developing World, taken together, but a case is starting to emerge for including the continent in a portfolio.  I expect that this resurgence is a little fragile; were China, for example, to lose its need for African raw materials, things could take a turn for the worse.

Also, despite the enthusiasm of some fund management companies, it is not an easy place to invest and the local stock markets will not have much capacity for major inflows of capital.  In investment terms, Sub-Saharan Africa tends to mean South Africa plus stocks in companies involved in mining, for instance.  The political risks are considerable in much of the continent and it is probably a long way off being seen as a new China were, for all its faults, the government is seen as stable and not wholly irrational.