How do they do this? categories before url

check out this website;
Code:
httpslash slash)privacy-software-review.toptenreviews.com/
look at the url, now click on one of the categories ie electronics

how do they get the category to show in url before the website name??

is this a script and if so what script.

Do you mean the subdomains?

product.site.com is a subdomain.

I don't know why i didn't think of that. That's exactly what i mean

thanks Bass tracker boats