Individuals who approach one on the street with unsolicited literature or requests, such as free newspapers, The Big Issue, flyers, requests for money, 'Charity Muggers', religious apologists, petition carriers, etc. These individuals in Britain have replaced the now banned practices of cold calling, email spamming and junk mailing, as the only thing charities/companies don't need permission for any more is invasion of personal space and public harassment.
"I am late because I had to do the Human Spam Slalom down the high street."
A person who is incredibly annoying and worthless in a situation. Someone who cannot add meaning, quality or substance to a solution.
"That guy from the computer store was total Human Spam. He couldn't even explain what he was talking about. His presence at the meeting was a waste."