Agents have been using blogs as tear books for some time now. I think Redux was one of the first with their blog reduxpictures.com/blog and now many agents have some form of the tear/news/announcements blog: bigleo.com/den, llreps.wordpress.com.
A few have taken it a step further like the Glasshouse Images stone-thrower.com blog where Jacqueline interviews their photographers along with photo editors and art buyers and the Art and Commerce Production artandcommerceproduction.com/blog where they combine photographer news with go-see’s. There’s a similar approach over on Stockland Martel’s blog stocklandmartelblog.com where Kristina combines industry news with the goings on of their photographers.
Finally Bernstein and Andrulli have turned their entire website into a blog ba-reps.com and I have to say the results are quite nice. An emphasis on social marketing may be in the future for everyone working in media. Check out the Crispin Porter + Bogusky website: cpbgroup.com where they pull content about the agency from youtube, twitter and blogs.