An other product Google released is named Google Trends, which is much easier to understand than Google Co-op. It basically shows you Web search and news search volume over time, broken down by region, city and language. I did a pretty large write up of it at SEW Blog named Fun With Google Trends and Danny has a great break down of what it really is also.
I would like to offer one more example, here, as a bit of payback for Danny's comment on the SearchCast about the Australians Fond Of Google; Vegemite Getting Jealous. In short, I had no idea what Vegemite was, supposedly it is a "dark brown, salty food paste made from yeast extract" to spread on bread or something. Danny said it is like Skippy in the US. So I thought it would be particularly interesting to see Google Trends compare the two, specifically using languages and regions.
Google Trends result for Skippy, Vegemite:
Skippy is in blue and Vegemite is in red:
As you can see from the chart, Skippy is way more popular. :)
But let's break it down by region and we will see that in Australia, Vegemite is way more popular, way more. In New Zealand, Vegemite is also more popular then Skippy, but not by much. But Skippy wins in all the other countries.
How about language? Well, Skippy wins for popularity in that break down. Australians speak English, so you see how popular Vegemite is in Australia just by how close Vegemite comes to Skippy.
Pretty cool tool? But there are many other uses for this tool. You can use it to predict trends, plan your SEM PPC spend and much much more. Is it the say all and end all tool? Definitely not, we are not even sure what data is being used exactly for this. So use with caution.