Quora Ad Killer by Wrybread

Removes all ads, sponsored content, promoted content, and teasers for "premium" posts. Tries to leave all useful content in place. I wrote it because the other Quora ad blocker I found made the site unusable by also removing the upvote/downvote buttons and the sidebar. This tries to simply remove the ads and leave the site fully usable. Let me know if it misses any ads for you.

And note that if you make the extension's icon visible in the browser toolbar, it'll keep a running tally of how many ads it removes.