Twitter actually has an entire team dedicated to killing spam.
Their actually doing a pretty good job for the amount of spam they actually have to deal with. Once they figure out that people have started to use favorites to spam, they'll start killing those kind of spammers too.
Their actually doing a pretty good job for the amount of spam they actually have to deal with. Once they figure out that people have started to use favorites to spam, they'll start killing those kind of spammers too.