CP257: OnPageHasMicroDataIsbn

Has microdata ISBN in web page HTML source

Correlates having a microdata ISBN in the web page HTML source as a factor.

This factor correlates the presence of a micro data ISBN number (in the HTML source) with rankings.

This factor correlates the presence of the factor on page and not the amount of that factor.

You can learn more about the targeted zone for this factor at: http://schema.org/isbn.