One of the perpetual risks you will run into when using smaller ad networks is that they are more prone to infiltration by spyware/trojan/virus drive-by-download advertisers. You may think this has to do with their lack of ability to filter such crap out. In reality though I think it has to do with their willingness to moreso look the other way, if they had people manually approving ads and working with advertisers this wouldn’t happen.
On my one site that uses Adbrite I’ve had numerous people, mostly UK residents, end up with these problems, although I myself had my anti-virus filter triggered once. This has been going on for weeks.
I’ve gotten one response from them about it:
We apologize for the ongoing perpetuation of unauthorized advertisements, such as drivecleaner.com, systemdoctor.com, or errorsafe.com in our network. We would like to notify you that in order to achieve a thorough and lasting resolution to this issue we have tightened restrictions around the submission of ad copy, begun scanning all advertisements for potential abuse, and forged partnerships with established anti-spyware and internet security companies to ensure detection and removal of these ads. Locating offending advertisers unfortunately continues to pose several difficulties. To that extent, if you are still experiencing problems with any advertisements that you believe to be abusing our network, we would appreciate any information you could provide about these ads, particularly the following:
But that was last week and this week its worse than ever.
If you use Adbrite check your site out, and you might want to suspend the ad serving until they get this fixed.