What is a good anti-spam software

Regular Yahoo mail. I keep getting nonsense from all over the place some have my real name which I never use.

 

Yahoo has got some spam controls of it's own. If you go to mail options then spam you'll find a few good settings which you can use to reduce the amount of spam you get. If you add just a domain name ie blah.com to the list of blocked addresses then that in turn blocks any email from that domain. Also you can set up disposible email addresses to use if you want to sign up for things and are wary about who might end up with your email address.
You have to keep an eye on your Spam folder tho as occasionally something you want might end up in there, however once you've highlighted it in the spam folder and clicked the "Not Spam" button it will remember for next time.