Don’t miss Diomidis D. Spinellis analysis of the impact factor of CS journals in 2010. One of the trends (more anecdotal than anything but still…) is that the impact factor of software engineeering journals is globally decreasing.
Given the importance that government agencies give to impact factors (something with which I don’t agree but that’s a different story) this trend is for sure something we need to follow carefully.
Another interesting fact from the analysis is to see that the impact factor of some journals bounces a lot. In countries (like Spain) where the government gives “extra points” for publishing in journals classified in the first 33% of their category, I can imagine that researchers must have a very hard time when trying to decide where to send their papers (needless to say that in the end, the decision is based more on these extra-scientific factors than on purely scientific reasons).