Is it really that hard to differeant?
Griefers are generally people who destroy others work, through whatever means possible, no matter how long it takes.
Trolls are just as manipulative but don't really destroy anything, instead usually make somebody or a group of people angry or upset, through whatever means possible. A broader term.
Both terms get thrown around so much that they've almost lost their meaning.
Kind of like how people on Facebook go "haxed by katie XXDD <333 u~~~".
Misuse of the term.