Metadata markup

<meta name="twitter:card" content="summary">
<meta name="twitter:site" content="@adactio">
<meta name="twitter:url" property="og:url" content="https://adactio.com/journal/9881">
<meta name="twitter:title" property="og:title" content="Metadata markup">
<meta name="twitter:description" property="og:description" content="So many standards to choose from.">
<meta name="twitter:image" property="og:image" content="https://adactio.com/icon.png">