Websites and blogs have had sidebars for a long time, but do you still need one? Not really. Now that responsive design is the standard and user experience has become crucial, sidebars are being retired.
But I Need a Sidebar!
I need to have related posts, popular posts, tags, newsletter signup, social links or ads in a sidebar. No you don't. You just need to rethink how these are implemented. Sidebars are mostly ignored and are certainly distracting from your content. I understand you want all of your website's visitors to easily navigate your site or connect socially. Simple navigation, site search, related links at the end of your blog posts and social links in the footer are all you need.
Responsive is the Standard
Responsive design and grid-based thinking has eliminated the need of a sidebar. With so many devices, such as tablets and phones, the need of a sidebar just doesn't exist anymore.
Focus on User Experience
UX (User Experience) has become extremely important, and Google thinks so too. Not only does focusing on your users improve your brand and interaction, it also gets you higher rankings in Google. An example would be having a mobile-friendly site, which you can use this test for.
Wrapping It Up
Sidebars are dead. Focus on ensuring perfect presentation of your content across all devices and making your website's visitors happy.