[adPothier]

Combined with AdBlock, I use Ghostery[1], which is a nice add-on (Chrome/FF/Safari/Opera/IE) : it blocks any javascript from ads networks, but also from analytics, trackers, socials plugins (and more) , and also cookies from the same trackers. Everything is configurable per-tracker and per-website.

It's quite a must-have if you don't want to be the product on the Internet. And a good failover over Ad-block.

[1]. http://www.ghostery.com/

[guelo]

The Ghostery extension tracks you and sells the data to ad companies, https://news.ycombinator.com/item?id=5897682

[StacyC]

Agreed on Ghostery. I have been using it for quite a while and it seems to work well.