Adblock Plus is a Firefox add-on that makes ads disappear (and has plenty of other useful features, too).
Just install the tool, restart Firefox and it'll begin filtering your web pages immediately. Most, if not all of those annoying Flash ads will disappear right away, speeding up your browsing and allowing you to concentrate on the site content.
The program hasn't worked for you? Adblock Plus provides a choice of more than 40 filters, and you can choose the ones that are most effective for you.
There are filters for many languages beyond just English, for instance, from Dutch, French and German, to Chinese, Vietnamese, Japanese, and more.
And you can also install filters for many specific purposes: to block ads on adult or P2P websites, to protect you from privacy risks, keep you safe from known malware domains, and even a blacklist for known Rickrolling pages (no, really...).
What's new in 3.1 (see Release Notes for more):
- Added the $csp filter option (issue 5241).
- Requests sent by Shared/Service Workers are now matched in the context of the document that caused the worker to spawn, i.e. requests sent from the worker are now also subject to document-based whitelisting and domain-specific filters (issue 6543).
- Users with corrupted storage are now notified and instructed to reinstall Adblock Plus (issue 6599).
- Fixed: Videos (and other media elements) remained hidden if they previously attempt to stream a blocked resource (e.g. a pre-roll ad) but then changed their URL (issue 5899).
- Fixed: Exception rules for element hiding emulation filters were considered invalid when adding custom filters (issue 6139).
- Improved performance of element hiding emulation filters (issue 6437).