Here is my "Global Similarity" provided by 23andMe. I'm closet to English, French, German, and Norwegian. I've included screen shots of each level of detail. I'm the red bar and then I'm the green dot as it gets more detailed.
Here is a high level "painting" of my chromosomes. They only use three populations in this tool and it's pretty conservative. My results were 100% Europe.
Ancestry Finder allows you to see where some of the people that match your chromosomes are from. Of course you have to complete the survey to have your data included, and many have not done this or any of the surveys. Since 23andMe have a large user base in the United States, many of my matches are here. Next highest are Ireland then the United Kingdom. This isn't surprising to me considering my known genealogy.
23andMe decribes the tool by saying "Let the 23andMe Community help you discover what countries your ancestors might have lived in. This lab is fueled by your responses to the "Where Are You From?" ancestry survey."
Digging DeeperI also sent my data to Dr. Doug McDonald who analyzed my Family Finder data last year. Dr. McDonald uses a higher resolution process so you can find things that the 23andMe tool might miss. I have a little American Indian, some African, and some South Asian. These could all just be ancestral pieces of DNA that exsist in the general population.