The interviewer is checking to see if you have checked out their blog, or even their social presence, to know the tone and approach they are taking. When asked to give feedback in an interview, its best to show your expertise but keep your opinions lighter to avoid offending anyone, or trying to reinvent the wheel. Discuss what you would do to increase readership and boost social shares. Now is the time to show off your social media skills and knowledge!
"I had a long look at your blog and love that you cover a range of topics. One suggestion that I would make is to tag your blog posts and organize them so that it's easier for your readers to find articles on topics in which they are most interested. I think this would make their experience more enjoyable, making them more willing to share what they find."
"There is a lot of amazing content on your website, and my biggest suggestion would be to add a more obvious social sharing button. It took me a minute to find it when I wanted to share one of your articles. To make the content more compelling, I would suggest the use of more gifs, videos, and interactive graphics."