Our AdRater system accumulates information on web advertisers. We are using this to evaluate the quality of advertisers accepted by different advertising services.
| Sites | Percent | Rating |
|---|---|---|
| 695 | 13.9% | Site ownership and business identity verified. No significant issues found. |
| 1975 | 39.5% | Site ownership identified but not verified. |
| 543 | 10.9% | No information available. |
| 1790 | 35.8% | Site ownership unknown or questionable, or significant negative information about the business was found. |
A rather high fraction of Google AdSense advertisers are rated as “site ownership unknown or questionable, or significant negative information about the business was found.” These are the ones for which we could not find the business behind the web site. We suggest dealing with such sites with caution. Users with AdRater installed will see the 
icon displayed atop ads for such sites.