There are much SPAM mails in yhaoo mail

I have been using Gmail only since it had introduced. Previously i was used Yahoo mail, in that i will receive mails only from spammers and even i can not able to check my friends mail,. that much spam mails i will have in Yahoo. We really do not know how the spammers got all of our email ID's. Yahoo can stop this spammers. But i do not know also as to why Yahoo did not been initiating any action plan for this. Thank you

yahoo puts mails in spam alot even impotant mails

Yep yahoo mail is full of spam. I think yahoo puts a lot of the spam there themselves. Yahoo has a spam folder that is suppose to collect spam related material, but it doesn't work. You'll notice that the things you mark as not spam end up there anyway, and the things that you mark as spam still go to your regular email. I recommend you use something other than yahoo.