This spreadsheet lets you compare 10 tweeters on the basis of who they follow (mostly). It summarizes the data about the people they follow by adding and averaging the number of people followed and following each. In other words (this becomes hard to explain), it tells me how many people follow the people I follow - in total, and on average.... as well as some other stuff.... and it does that for 10 tweeters at a time so you can compare them. In the sample, we compare barackobama to coldplay to jrochelle (who the heck is he?) to oprah.
This spreadsheet is a great example of using the ImportXML() command in Google spreadsheets. It has many example formulas where different xpath command strings pull different data points or summaries of data. Use the "get your own copy" link below if you want to see the formulas in the spredsheet which achieve those XML data grabs.
Here's a link to the spreadsheet below just for viewing or get your own copy of the spreadsheet if you want to edit it and compare your own list of 10 tweeters.