First, a caveat for those literalists out there.  Sure, a worse networking mistake would be to sell all of your friends' names and contact info to a spam organization.  Or end every coffee appointment you hold with an enormous belch.  Or send everybody you know an e-mail telling them you think they smell and have bad taste in clothing. But in terms of the regular day-to-day stuff people do wrong, there's one "networking sin" that [...]