The Archdiocse of New Orleans has called upon Catholics to refuse to patronize (boycott?) contractors involved in building a new Planned Parenthood facility. 

There were rumors that the NFL might refuse to patronize (boycott?) the state of Arizona for the Superbowl, if the governor signed a law that expanded rights of business owners to refuse to patronize (boycott?) customers if doing so violated their religious beliefs. 

A gay hairdresser refused to cut the hair of the governor of New Mexico (boycott?)  because he didn't agree with her stance on same-sex marriage.( HT Deacon's Bench)

What, exactly, is a boycott? Does refusing service in a particular case, for whatever reason, count as a little boycott? Or do you need to try to organize? How do we analyze the morality of boycotts? Is that analysis entirely reducible ot the morality of the underlying cause?

Can we distinguish between boycotting something and impermissible cooperation with evil? It may not be impermissible cooperation with evil to shop at a big box store, but I may choose to boycott it anyway, in order to change (say) child labor practices of its suppliers.

Any thoughts on how we should think about boycotts? They are not just a liberal, or a conservative tactic. They can be used by both sides in any controversy. Though: 1) in order to be necessary, you'd need to be trying to change the majority culture in some way; and 2) in order to effective, you'd need to have a substantial minority on your side. 

What do you think?