All issues found during a crawl will be categorized by type in the Site Auditor. The Issues by Type chart can help identify which types of issues are most common on your site by showing the number of URLs affected by each category.
There are 7 types of issues in the Site Auditor:
Issues regarding content visible on the page to site visitors
Issues regarding redirected content
Issues with meta tags, such as Title, Meta Description or Meta Keywords
URLs that have been assigned targeted keywords, but the keywords were not found in the main content areas of the page.
Issues associated with content being accessible to search engines
Issues where content is not available due to errors
All other issues that don't fit into one of the above categories