This is a good article worth reading: Why the New Guy Can’t Code. It’s a little heavy handed, but it makes sense and there’s one great quote: don’t interview anyone who hasn’t accomplished anything. Ever.
I think we are starting to see this, with all the research that hiring managers and HR people can do online about applicants. If you don’t have some body of work, some evidence that you have the skills needed for the job, why bother with the interview?
Blogging, building a project, having some volunteer projects or applications you’ve built on the side can bring some depth and color to your application, and it gives you the chance to let the interviewer know about your accomplishments when they are considering calling you.
It removes some level of doubt that you might not be a good fit, and it gives you the chance to make a positive first impression early. That’s half the battle of finding your dream job.