A user, possibly a marketer, onTwitter or other mini-blog tool who 'follows' every user they come across, hoping that this will in turn mean that they get 'followed'.
A chocolate bar marketing agent opens an account on Twitter and then trawls through the network, finds as many people as they can and 'follows' them (i.e. to receive their updates). The agent hopes that many of those they follow will reciprocate and follow their brand, opening the door for their marketing messages. This agent is a 'Storker'.