The Google+ rel=publisher is a part of a knowledge graph that allows the Google engine to more readily find information about a specific business website. The rel=publisher tag is placed within the header <head> </head>section of your website.
Right now, there is limited perceived value that Rel=Publisher provides a website. Currently, its greatest contribution to a website is that when branded search queries are made in Google, the Knowledge Graph for that question should display a widget for that brand’s corresponding Google+ page which includes:
Name of Google+ Page
How many followers the page has
When page was lastly updated
Option to start following the page, if the user is signed in
For businesses that have a physical location and have that data properly filled out on their corresponding G+ page, having the Rel=Publisher tag implemented may also help to ensure that this data is correctly displayed in the Knowledge Graph.
Some other than this benefit, there remains only speculation as to what the Publisher tag can or will do for a website. Google has been increasing the value they put behind the Rel=Author tag as part of their algorithm use for ranking content, and there is speculation that the Publisher tag will eventually be used to further refine Google’s SERPs. The Publisher tag may also be used as a unifying factor between multiple Rel=Author tagged profiles on a single domain, signification that the more high value authors are associated with a website, the better that website may do on a whole in search.
For now, remember that your website should be correctly using both Rel=Publisher and Rel=Author tags if applicable. Cogitate of the Rel=Publisher tag as a yellow pages listing for a business, and Rel=Author tag as business cards for individuals. Both serve different purposes but are both important for the business to succeed.
- It allows Google to recognize your page, thus displaying page information within search results.
- Adding the rel=publisher tag and sharing on your Google+ Local page increases your visibility in Google’s search results.
- Implementing the publisher tag is a simple way to help boost your SEO.
Here is the free Google Markup Tool to check your site has a verified publisher markup code correctly implemented.