The Jargon File (version 4.4.7, 29 Dec 2003):

blogrolling


    [From the American political term ?logrolling?, for supporting another's
    pet bill in the legislature in exchange for reciprocal support,] When you
    hotlink to other bloggers' blogs (and-or other bloggers' specific blog
    entries) in your blog, you are blogrolling. This is frequently reciprocal.