I posted a reply to a comment on an article using my fake name and the next day a "friend" says "Wow I saw your posting at the Daily News. I was shocked because I used a psuedonym. He claims there is a software he uses where he enters email addresses and can then see whatever I do online linked to that email account. How can I protect my privacy?
I've not heard of any such software. He would need access to the servers log files to do this. Perhaps he has your email accounts password and when you posted, the Daily News sent you replies of other people. Change your email password. More importantly, if you use a pseudonym, you should also use a different email address and not your mail one.
Privacy really has limited existence on the internet. You have to go to great lengths to protect yourself. Everything you do on the net can literally be traced back to your IP.