There are a few key pieces of metadata that you should always include when optimizing your website for SEO:  1. Title tags. These are the most important pieces of metadata on your website, as they tells search engines what your page is about. Make sure to include relevant keywords in your title tags, and keep them under 60 characters so they don't get cut off in the search results. 2. Meta descriptions. These give searchers a brief snapshot of what your page is about, so it's important to make them compelling and accurate. Again, include relevant keywords but also write for humans – remember, meta descriptions show up in the search results, so you want people to click through to your site. Keep them under 160 characters. 3. Image alt text. Whenever you include images on your website, be sure to use proper alt text so search engines can index them and people with vision impairments can still understand what's on the page. Include keywords here as well, but make sure they're relevant to the image. 4. H1 tags. These are the largest, most important headlines on your page, so you want to make sure they're optimized for SEO. Include keywords and keep them brief – around 60 characters or less. 5. H2 tags. These are the second-most important headlines on your page, and should be used to break up sections of text and make your content more scannable. Again, include keywords but keep them brief. I think social SEO metadata is a great way to help improve your search engine ranking and also to help people share your content on social media. I think it's especially important to use Schema markup, since it can help Google better understand the content on your website. I also think it's important to use Open Graph tags, since they can help control how your content looks when it's shared on Facebook. And I think Twitter Cards are a great way to get more exposure for your tweets. So I definitely recommend using all three of these types of metadata! By including these key pieces of metadata on your website, you can help improve your SEO and ensure that your site is properly indexed by search engines.