i have vbulletin forum with 3k visitors/day before it was 3.6.8 and every thing is ok with adsense ads now after i upgrade to 3.8.1 my advertises completely not targeted ,or related to my forum like this ads and link units not appears absolutely i tried many styles,i deleted cokies,see my site from google. i used these codes https://www.google.com/adsense/support/bin/answer.py?hl=en&answer=23168&safe=on i see my sites from many IPs and my friends in another countries but my ads still appear like picture anyhelp!
Do you have anything in your meta tags? Do you have a good forum description in the vboptions, do you have good long solid category descriptions for each category that can be seen by guest? I would start there..
i have everything ok before i was 3.6.8 all adsense seems ok but after i upgrade to 3.8.1 adsense gone why???
I had the same problem you did, the issue is that you need to redefine your meta key tags and keywords so that Google and streams the correct type of ads to your forum.
i have my metatags ok, and i cheked keywords denisty ,works well adsense appears in search pages like user posts and new posts but main forum pages,threads,forums adsense gone Strange!
I have a smf forum and every time I upgrade I have to put the adsense back in. Maybe you have to start from scratch and do the same thing. Maybe the upgrade has messed with the ad code??