What makes you a Twitter spammer?

Blocky (@blocky_bot, http://blocky.elliottkember.com) is a crowdsourcing 
solution for Twitter spam. Blocky does not define what a "spammer" is,
so let's discuss.

What makes you a Twitter spammer?

- You follow me just to make me follow you. 
  There's a good chance this applies when you start following me even though 
  you already are following 500+ people.

- You repeatedly tweet links to your own website(s)/service(s)/... whilst 
  rarely tweeting anything personal.
  Of course a sane ratio will be highly subjective. To me maybe tweeting your 
  ads more often than 1% makes you a spammer.

- You're on Twitter for the sole reason that someone told you there's "social 
  marketing".
  This definitely applies to anyone who "outsources" tweeting to someone 
  else/a service (looking at politicians). It probably also applies to SEO 
  people and other folks wanting to artificially raise attention or traffic.