Hobnob comes from an eariler phrase, to hob or nob, meaning "to drink together, taking turns toasting one another," probably from Middle English habbe "to have" and nabbe, a contraction of ne + habbe, "to have not," hence, "to have and have not, to give and take."
well. hobnob had to be decommed from it's glorious role as an interesting but disturbingly badly managed / maintained internal web server / box of stuff... this is it's replacement. it's on the internet as you can see. not nearly as much stuff of interest as the original but hey ho!