Bit of an unusual one this week - we have a new server and the software is much stricter about XML validation, so lots of the blogs aren't currently coming through in our feed. So our data set is much smaller and looks unrepresentative. So take "production" and "oil" with a pinch of salt. Anyway, the words moving up and down the chart are listed here.
I use Wordle to generate the image, the ROME RSS reader to download the RSS feeds, and Java software from Inon to process the data.
You can also see the Java version in the Wordle gallery.