Comment Optin Option

I noticed that in order to leave a comment in my blog, you must be “logged in” https://jackiebiz.com/2009/11/03/7-steps-to-put-an-end-to-business-mediocrity/

I just visited a blog where I did not have to do this. It also had a lot of comments https://www.thewaythatyouwander.com/what-does-lifestyle-design-mean-to-me/

Question:

1) How can I change my comments to be just like the one in thewaythatyouwander.com?

2) Would this create a lot of spam? or would Askimet still be able to block spam?

Thanks!