Spam

It means you have gotten youself added to a few spammer's lists. Unsubscribing was the worst thing you could do. That just confirmed that your email address was valid for the spammers and probably got you added to even more lists.

This is really not a malware issue. It is really more an issue that you have to be more careful who you give your email address to. You could try using spam filtering software. For that, you should ask for opinions in the Software Forum.

Another solution to use (if it really gets out of hand) is to change your email address. And then from now one be more careful where you post your email address. Get a second email account from a free source (like hotmail or yahoo...etc) and only use that email when buy stuff online or need to give an email address for any reason. Only use the email account that you don't want spam on with friends or work. Make sure your "friends" don't forward or send your email that is going to large groups. That is an easy way to join spam lists. Too many people forward to all people in the email list and this is problematic. If you have friends that like to forward or send you jokes or chain letters, DO NOT give them your new email address.