Can we help against spammers?

Is there any way we, as users, can help deal with the waves of spam-meds-bots? When I get the chance I downvote, but that's not possible for microblog. Do reporting them have any effect, or they go in the pile and are more a nuisance than a help?
If we blocked the culprit users, would it do anything other than us personally, even by just reducing their visibility?