What happens is, if you comment on someones page and someone else goes to their page they can see your comment and click on your name and go directly to your page, so then they can comment.
Yeah I've had a ton of comments from random people I have never met before. There's a meet someone new button on the first page that pops up when you click to go to mypage. I think that's how people find you. You can set up your mypage to show off your room designs and people can go view them. I think it's a neat feature.