Ways to receive negative karma: 1) Do any of the follow things on a new account  a) Ask for bitcoins  b) Promote an off-site service, especially one that charges money  c) Criticize something or spread FUD on an obvious shill account 2) Break forum rules, like advertising products when you're not a vendor 3) Criticize SR or DPR (this is where most of mine comes from) 4) Act overly stupid or trollish 5) Generally say something controversial that others disagree with This is an incomplete list but covers the most common cases.