Flash might be the preferred choice for delivering videos and rich media, but you cannot deny that it has also given rise to annoying ads with effects, popups and what not.
To hide annoying Flash advertisements on sites, you can get rid of Flash elements entirely, and then enable them selectively when, for example, you need to watch a YouTube video.
While this post is titled “in Chrome”, the userscript mentioned here works for Firefox also. All you need to do is have the Greasemonkey extension. Chrome users do not even need that, you can simply load the userscript as an extension.
Go to Flashblock page and hit the big green “Install” button, to remove Flash for good. To unblock Flash on a page, hit Alt+F.
Flash Block has an added feature – you can save Flash content (including videos) on direct links. That includes YouTube, so you now have a Flash blocker plus downloader rolled into one.
Blog Flash 2 is an alternative you can use in case Flash Block does not work for some reason.