I never knew that using the old contacts would help me to network in a brave new world of public libraries. It never hurts to get in touch with old friends or bosses you may haven't spoken to in a while to get some of their personal feedback on the job market, their experiences and views of the necessary skills employers are looking for, especially research skills. You may be overlooking a lot of juicy information, like your quirkiness, that friends have on hand. Letters are great, but blogging, email, listservs, conferences, hell, even shopping can do wonders for the old network.
Suddenly business cards have blog or urls on them to exchange not just opportunities but also personal information that can be helpful to those who want the inside feel of a company.