Are you extending another template that uses all these sections? They won't work on their own, they need to populate a placeholder in another template.
It should be something like:
<!-- layouts.master -->
<html>
<head>
<title>App Name - @yield('title')</title>
<meta name="description" content="@yield('description')">
<meta name="keywords" content="@yield('keywords')">
<!-- etc -->
</head>
<body>
...
</body>
</html>
And then your template should extend the other template.
@extends('layouts.master')
@section('title')
{{trans('strings.About')}}
@stop
@section('description', 'Share text and photos with your friends and have fun')
@section('keywords', 'sharing, sharing text, text, sharing photo, photo,')
@section('robots', 'index, follow')
@section('revisit-after', 'content="3 days')
At least, that is how I read their documentation: https://laravel.com/docs/5.2/blade
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