Effective use of WordPress

I have been blogging using wordpress for the past year. There a couple of things that I am a bit confused about and I am hoping that someone can give me an answer.

1. I get quite a few comments that I believe are spam comments they are simply repeated comments but appear to be coming from different subscribers.

2. How can I tell if those that are subscribing are legitimate as there are many that are hotmail.com addresses or outlook.com addresses.

Any insight or help is greatly appreciated.