I think you guys need to check either your website code, or some of your advertisements.
I came to WGT today and it immediately started executing Antivirus 2012, which is a rogue AV.
I came back and didn't have the issue, but it for sure came from the WGT site, not sure if it was an advertisement that it came from (that is how they execute that rogue AV a lot of times, Weather.com, eBay just to name a couple that was caught by this in advertisements.) or if you have someone that has found a backdoor to your website and added some malicious code.
But I think a check is in order for the code....whether it be on the website, or in an ad.