Google tells their quality checkers to look at the page as a whole. Here are some of the things they are looking for.
Google looks for these spam signals:
- PPC ads very prominent on the page.
- Copied content.
- If you remove the low quality page elements (ads & copied content), the page has no other value.
They also look for these positive page signals:
- Page is well-organized.
- Ads are well identified and not distracting.
- Content is original or the top ranking result.
- The page has value to the user.
If you are unsure about your webpages ask yourself:
- Does your page provide a good user experience?
- Does your page contain original content that is helpful?
- Is the page designed for human users?
- If you remove the ads and copied content, is there a good amount of helpful resource left?