Google's John Mueller recently responded to a Reddit question about indexing items placed before the primary content in a post.

The query concerned putting material, such as banner ads, before the main post via a hook in a WordPress theme.

Also, regarding how GoogleBot handles SUCH types of content. Specifically, is it flagged as duplicate content or not?

According to Mueller's response, you cannot simply noindex a part of a page like that to prevent it from getting indexed. However, there are alternative methods to enhance SEO and clarify the structure of your webpage for Google.

John's response to the question is below.

Key Takeaways

Semantic HTML elements help Google recognize the various components of your webpage.

In fact, Google views a website in sections, such as its header, navigation, main content, sidebars, and footer. Indexing generally considers everything outside the main content area to be less relevant.

Google treats the header, navigation, and footer differently when they contain the same sitewide content. Nevertheless, the main content deserves special attention for better SEO. Marking up the main content with HTML elements makes it more visible and identifiable to Google.

Use HTML elements to separate ads from the main content if you have them. While Google can typically figure out what content belongs to the main post, using semantic HTML markup will make it easier.

Google identifies boilerplate content separately from the main content. So, make sure to place HTML elements properly to make sure everything is clear for Googlebot.

Attempting to hide advertising on your page is not recommended. Instead, you can utilize the <mark> element to indicate it clearly as an advertisement. In this way, Google's indexing and ranking algorithms will be transparent.

To optimize your webpage for better SEO and indexing, you can use semantic HTML elements to distinguish between main content and advertising.