The usual cause of those ‘ads not by Facebook‘ are from some browser add-on (extension, toolbar, plugin) installed on your computer.
The add-ons you will be looking for are Facetheme, Beautify Facebook, facicons, Yontoo Layers, Smiley Central, Smiley District, PageRage Toolbar, Crush Revealed, Secret Crush Revealer, Webfetti, Bandoo, Celtic, Angels, Alot, Game Play Labs, HyperCam toolbar, Babylon toolbar, BCool, Video Saver, Amazing Apps, Fantapper, Dislike Button, SweetIm, Better Facebook, Youtube plug-in, on Chrome also look for a ‘Linked-in’ extension, ‘photo zoom app’, I Want This!, DivX Plus Web Player HTML5, 1clickdownload, Codec-C(an add-on that may come with an update for your media player), Timeline Remover, Research–with no publisher, etc.
I recommend you disable suspicious add-on, if that resolves your problem then you can remove the program from your computer otherwise you can re-enable the add-on. You may have to restart your browser for the disable to take effect.
BROWSER/DISABLE ADD-ON TECHNIQUE
IE 7: Open browser. Click “Tools”, click “manage add-ons”, click “Enable or Disable Add-ons”, in the “Show” list click “Add-ons currently loaded in Internet Explorer”, click the add-on you want to disable and under “Settings” click “Disable”.
IE 8: Open browser. Click “Tools”, click “manage add-ons”, under “Show” click “All add-ons”, click add-on you want to disable, then click “Disable”.
IE 9: Open browser. On browser toolbar click the little gear icon, click ‘Manage add-ons’, in the ‘Show:’ box change to ‘All add-ons’, click suspicious add-on to highlight and select ‘Disable’ in the lower right of window.
GOOGLE CHROME: Open browser. Click customize(wrench) > Tools > extensions > disable add-on desired.
FIREFOX: Open browser. Click menu > Tools > Add-ons > disable add-on desired.
SAFARI 2.x: From Safari menu select ‘Preferences’, click the ‘Security’ tab, uncheck ‘Enable Plug-ins’, click OK, close and relaunch your Internet browser.
SAFARI 3.x: Click the Safari menu, select ‘Preferences’, select ‘Security’ tab, remove check from ‘Enable Plug-ins’.
The program files for the add-ons are not deleted by the above. They can be re-enabled. To permanently remove the program files on PCs: Start > Control Panel > Add/Remove Programs (on Windows 7 operating system this is ‘Programs and Features’ folder) > select program and click delete. You will need to restart your computer.
It is a good idea to clear your browser cache and cookies also.
I use google chrome and it was very annoying so maybe you find this helpfull.