The Adblock extension is a wonderful little add-on to keep unwanted ads from showing up in to the open source Firefox web browser. Another nice thing about Adblock is that pages load more quickly without the ads, since Firefox never even tries to read the blocked images or access the sites that host them. Blocking ads allows Firefox to get on with loading the rest of the page, which is especially helpful when the site where ads are located is slow or down.
I don't bother to block text-only or small, unobtrusive ads, just the annoying popup, flashy banner, or other annoying disruptions to my online experience.
Sometimes I'll be browsing along and an explicit adult ad will show up. Adblock to the rescue!
You can export and import your Adblock list to or from a text file, to keep your list synchronized from computer to computer, or to import the filters to several computers, such as for a client installation.
You can also add someone else's filters to your own. For example, below is my Adblock filter list, which you can either cut and paste to a text file of your choice, or right-click this link to download.
In Firefox, choose Tools ->Adblock ->[Preferences].
After you have downloaded or created the filter file, from the Adblock Preferences box, choose Adblock Options ->Import, which will bring up a standard File Open box for your system. Select the file, and the filters will be added to your own.