I have stopped using the traditional hosts file, because
1. a large file slows down browsing (at least on my not exactly state of the art system)
2. too many items will be missed, no matter how many entries you add. 10, 20, 30, ... doubleclick items still leaves gazillions of sites uncovered.
I have switched to a local DNS proxy: http://mayakron.altervista.org/support/ ... th=Acrylic
It also uses a hosts file, but this accepts wild-cards. So, for example, *doubleclick* or *.doubleclick.* will block them all, on every site. Based on the log file, I have added about 900 entries to the hosts file. For me it's an effective system and yet lighter than the regular hosts file.
On topic: this is the one I used to work with:http://someonewhocares.org/hosts/