1) Share your experience and help others- Other people are looking for jobs too, other people are having the same frustrations you are....so why not share and build your own community. You'll feel better about each interview and with a little luck find a few folks who you can use to bounce ideas off of as well as do a little networking. Think about it, you interview at Company X and find that the deli across the street was a fantastic place for a coffee before you go into the meeting. I'm sure other candidates would love to have a great place to grab their pre-interview coffee **Disclaimer - if you have to sign an NDA, don't share anything that would put you in violation!**
2) Get your thoughts down, in writing - Ever leave an interview and have a full range of emotions? It was great! It was terrible! The LOVE me! Well, what better way to put your immediate thoughts down than to write a quick blog once you are done. This forum will also allow you to send it to your friends and colleagues to get their thoughts. Rarely will you get instant honest feedback from the company about your interview, why not get your thoughts/impressions out to your network and see what they think. I think you'll be surprised at some of the tips and advice you'll get **Same NDA advice here**
3) Polish up your skills - Write much? I'm a terrible writer but blogging has helped me polish up my skills (UNH education here...) I'll never be mistaken for Hemingway but blogging allows you to show the world what you've got. Blog about your interviews, resume, experience, luck with job boards, distaste for job fairs, networking expertise, you name it, blogging about your experience will help you reflect on things and improve yourself.
4) Show people you care - Blogging means you are passionate about something. Props to @garyv (www.garyvaynerchuk.com) for really showing me the way on this topic. If you are passionate about your job search, blogging will show people you care and allow you to tell the world "Yes I'm looking for a job, and proud of it".
5) Social Media is the Future - Duh right? File that under "cliche'" but it's true. Using your blog or twitter account to thank your interviewers is cool. I've had several candidates ping me via Twitter or blog about their experience with me and think it's cool. It's a great way to say "thank you" but also to show the company you "get it" and are someone who's got an eye on the future. **Last disclaimer - don't trash people in your blog, it's poor taste, never goes a way and send the WRONG message no matter how much the other person might deserve it"