Our landing page quality guidelines have always stressed the importance of directing users to easily navigable landing pages that are transparent about the advertiser's business and that contain relevant and original content. In our ongoing effort to provide advertisers greater transparency about our approach to landing page quality, we recently created a new FAQ in the AdWords Help Center outlining the types of business models that users have consistently commented on as providing a poor experience. You can find the new FAQ here -- and below, we've highlighted the most important points:

Types of websites that will be penalized with low landing page quality scores:
  • Data collection sites that offer free gifts, subscription services etc., in order to collect private information
  • Arbitrage sites that are designed for the sole purpose of showing ads
  • Malware sites that knowingly or unknowingly install software on a visitor's computer
If we receive user complaints about ads for the types of websites listed above, the advertisers of those websites may not be allowed to continue running AdWords ads for those websites.

The following types of websites are likely to merit low landing page quality scores and may be difficult to advertise affordably. In addition, it's important for advertisers of these types of websites to adhere to our landing page quality guidelines regarding unique content.
  • eBook sites that show frequent ads
  • 'Get rich quick' sites
  • Comparison shopping sites
  • Travel aggregators
  • Affiliates that don't comply with our affiliate guidelines
Please note that all of the above information, along with further details regarding landing page quality may be found in the AdWords Help Center.

Lastly, you may recall past Inside AdWords blog notices alerting advertisers about upcoming landing page quality updates. Since our systems frequently visit landing pages and update Quality Scores on a regular basis, we will no longer post advance notice of upcoming updates. We will, however, continue to inform you of any significant changes to landing page quality guidelines or the factors which are considered in calculating landing page quality.

Update: Clarified text for 'eBook sites'