When someone I'm interviewing mentions this blog, I know s/he did his/her homework. Not only did s/he research the company, s/he also researched me. It shows genuine interest in the job, and respect for the company. But even if I wasn't part of his/her Google search, at the very least I expect interview candidates to read our company website. There's no excuse not to.
Every magazine now has a website. Prepare for an interview by reading it. If you have more time, also read the magazine's Facebook page, blogs and Twitter stream. Think about it this way: If you can't take 20 minutes to read our website, why should I waste 20 minutes talking to you about a job/internship opportunity?