The impact of a "Read More" button on SEO depends on how it is implemented and used on a webpage. In general, search engines aim to understand and rank content based on relevance, quality, and user experience. Here are some factors to consider:

1. Content Accessibility: If the "Read More" button is used to hide content from the initial view and only expands when clicked, search engines may not index the hidden content. This can potentially affect SEO because search engines rely on the indexed content to determine relevance to user queries.

2. Mobile Friendliness: "Read More" buttons are often used to improve the mobile user experience by condensing content. Google prioritizes mobile-friendly websites in its rankings, so a well-implemented "Read More" button that enhances mobile usability can be beneficial.

3. Page Load Speed: If the "Read More" button is implemented in a way that reduces the amount of content loaded initially, it can contribute to faster page load times. Page speed is a known ranking factor, and faster-loading pages generally provide a better user experience.

4. Content Structure: Search engines analyze the structure of the content on a page to understand its organization and relevance. If the "Read More" button is used to break content into logical sections, it can help search engines better understand the page's structure and context.

5. Anchor Text: If the "Read More" button is linked to additional content, the anchor text of the link can influence SEO. Descriptive and relevant anchor text provides context to search engines about the linked content.

6. User Experience: The overall user experience is crucial for SEO. If the "Read More" button enhances navigation and readability for users, it can positively impact SEO indirectly by improving user satisfaction.

On the other hand, if the "Read More" button is used to manipulate content for SEO purposes without providing real value to users, it may be viewed negatively by search engines.

In summary, the use of a "Read More" button itself is not inherently good or bad for SEO. It depends on how it is implemented and whether it enhances the user experience and content accessibility for both users and search engines.