Earlier quoted context omitted.
I've discovered you can also set up a Custom Search Engine, with no included sites (default to everything), and specifically exclude the sites you don't want. Then do all your searches through this. http://www.google.com/cse/ Usability-wise, though, it's not nearly as much use as a 'ban' button next to each result would be. But it shows Google already have the infrastructure and code that would allow this -- they jus…
But its not free, right ?
"Standard edition - ads are required on search pages"
There's an ad-free premium version as well, but you definitely can get it for free.