PLEASE NOTE:
This is a post I made a few years back that I’ve bumped to the top, sadly my S2000 was sold ages ago and now I have Google Ads 
Adblock is a great extension to add to Firefox to bannish annoying adverts. I contribute to www.s2ki.co.uk; a forum for Honda S2000 owners and enthusiasts, but I’m not a paid up member of the forum but just a ‘guest’. If I was a paid member I would see less ads and if I was a gold member I would see no ads, but why pay for this when you can do it for free!
Get the software
Firstly get Firefox from http://www.getfirefox.com and install
Once installed and running get the Adblock extension from http://adblock.mozdev.org/
Go to the above url:
Click the Install link.
Click on Dev. Builds link (Adblock is an extension in progress and not final but its very stable and works well).
Scroll down the page a little and then click on the Adblock link, current version is Adblock 0.5 d3 nightly 42 , obviously the link name will change as Adblock is updated.
If you have not installed software from this site before (and as you are reading this you probably have not) then Firefox will warn you that it has prevented this site from installing software on this computer;. Now obviously we want the software so click on the Edit Option; button.
Once you have clicked on the "Edit Options" button a dialogue box will appear asking if you want to add this site to your allow list. Click the "Allow" button then dismiss the dialogue box (on OS X click the red dot on the top left of the box).
Now click on the Adblock link again.
A box will appear confirming you want to install, you may have to wait a few seconds before you can click the "Install Now" button. On clicking the "Install Now" the extension will download and install. You now need to QUIT and RESTART Firefox for the extension to become active.
After restarting your browser in the bottom status bar (assuming you have it visible) you will see Adblock. You may have other items to the left or right of it like I have, these are other extensions.
Now go to the site you want to block ads from. In this exampe I’m using the s2ki.co.uk site, I’ve gone into a thread and as you can see below the first post in the thread is an advert. Right click some where in the advert, from the menu that appears select "Adblock iFrame".
A box will appear showing the URL of the advert. Now here is where it gets a little more interesting, we don’t want to just block this URL as it only point to this advert. What we need to do is edit URL and add a * which acts as a wildcard meaing that anything after where you add the * will be blocked:
E.g. Current URL will be a very long and may look something like:
http://pagead2.googlesyndication.com/pagead/ads?client=ca-pub-2030797261146040&dt=1140175279684&lmt=1140175278&alternate_ad_url=http%3A%2F%2Fwww.s2ki.com%2FAds%2Fadview.php%3Fcampaignid%3D1&prev_fmts=728×15_0ads_al&format=728×90_as&output=html&channel=4625244836&url=http%3A%2F%2Fwww.s2ki.com%2Fforums%2Findex.php%3Fshowtopic%3D361764&color_bg=EEEEEE&color_text=000000&color_link=0088FF&color_url=0066CC&color_border=EEEEEE&ad_type=text_image&ref=http%3A%2F%2Fwww.s2ki.com%2Fforums%2Findex.php%3Fshowforum%3D25&cc=100&u_h=1024&u_w=1280&u_ah=1024&u_aw=1280&u_cd=32&u_his=7&u_java=true&u_nplug=15&u_nmime=124
Change to:
http://pagead2.googlesyndication.com/pagead/*
This will block all ads being requested from that address not only on this site but on every site you visit.
Once you have edited the URL and added the * click the "OK" button.
You will now notice the advert has GONE! No more annoying ads.
